Method for smart energy device infrastructure

ABSTRACT

A method for characterizing a state of an end effector of an ultrasonic device is disclosed. The ultrasonic device including an electromechanical ultrasonic system defined by a predetermined resonant frequency. The electromechanical ultrasonic system further including an ultrasonic transducer coupled to an ultrasonic blade. The method including applying, by an energy source, a power level to the ultrasonic transducer, measuring, by a control circuit coupled to a memory, an impedance value of the ultrasonic transducer, comparing, by the control circuit, the impedance value to a reference impedance value stored in the memory; classifying, by the control circuit, the impedance value based on the comparison; characterizing, by the control circuit, the state of the electromechanical ultrasonic system based on the classification of the impedance value; and adjusting, by the control circuit, the power level applied to the ultrasonic transducer based on the characterization of the state of the end effector.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. § 120 to U.S.patent application Ser. No. 16/209,458, titled METHOD FOR SMART ENERGYDEVICE INFRASTRUCTURE, filed Dec. 4, 2018, now U.S. Patent ApplicationPublication No. 2019/0201047, which claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 62/773,778, titledMETHOD FOR ADAPTIVE CONTROL SCHEMES FOR SURGICAL NETWORK CONTROL ANDINTERACTION, filed Nov. 30, 2018, to U.S. Provisional Patent ApplicationNo. 62/773,728, titled METHOD FOR SITUATIONAL AWARENESS FOR SURGICALNETWORK OR SURGICAL NETWORK CONNECTED DEVICE CAPABLE OF ADJUSTINGFUNCTION BASED ON A SENSED SITUATION OR USAGE, filed Nov. 30, 2018, toU.S. Provisional Patent Application No. 62/773,741, titled METHOD FORFACILITY DATA COLLECTION AND INTERPRETATION, filed Nov. 30, 2018, and toU.S. Provisional Patent Application No. 62/773,742, titled METHOD FORCIRCULAR STAPLER CONTROL ALGORITHM ADJUSTMENT BASED ON SITUATIONALAWARENESS, filed Nov. 30, 2018, the disclosure of each of which isherein incorporated by reference in its entirety.

U.S. patent application Ser. No. 16/209,458 claims priority under 35U.S.C. § 119(e) to U.S. Provisional Patent Application No. 62/750,529,titled METHOD FOR OPERATING A POWERED ARTICULATING MULTI-CLIP APPLIER,filed Oct. 25, 2018, to U.S. Provisional Patent Application No.62/750,539, titled SURGICAL CLIP APPLIER, filed Oct. 25, 2018, and toU.S. Provisional Patent Application No. 62/750,555, titled SURGICAL CLIPAPPLIER, filed Oct. 25, 2018, the disclosure of each of which is hereinincorporated by reference in its entirety.

U.S. patent application Ser. No. 16/209,458 also claims priority under35 U.S.C. § 119(e) to U.S. Provisional Patent Application No.62/729,183, titled CONTROL FOR A SURGICAL NETWORK OR SURGICAL NETWORKCONNECTED DEVICE THAT ADJUSTS ITS FUNCTION BASED ON A SENSED SITUATIONOR USAGE, filed Sep. 10, 2018, to U.S. Provisional Patent ApplicationNo. 62/729,177, titled AUTOMATED DATA SCALING, ALIGNMENT, AND ORGANIZINGBASED ON PREDEFINED PARAMETERS WITHIN A SURGICAL NETWORK BEFORETRANSMISSION, filed Sep. 10, 2018, to U.S. Provisional PatentApplication No. 62/729,176, titled INDIRECT COMMAND AND CONTROL OF AFIRST OPERATING ROOM SYSTEM THROUGH THE USE OF A SECOND OPERATING ROOMSYSTEM WITHIN A STERILE FIELD WHERE THE SECOND OPERATING ROOM SYSTEM HASPRIMARY AND SECONDARY OPERATING MODES, filed Sep. 10, 2018, to U.S.Provisional Patent Application No. 62/729,185, titled POWERED STAPLINGDEVICE THAT IS CAPABLE OF ADJUSTING FORCE, ADVANCEMENT SPEED, ANDOVERALL STROKE OF CUTTING MEMBER OF THE DEVICE BASED ON SENSED PARAMETEROF FIRING OR CLAMPING, filed Sep. 10, 2018, to U.S. Provisional PatentApplication No. 62/729,184, titled POWERED SURGICAL TOOL WITH APREDEFINED ADJUSTABLE CONTROL ALGORITHM FOR CONTROLLING AT LEAST ONE ENDEFFECTOR PARAMETER AND A MEANS FOR LIMITING THE ADJUSTMENT, filed Sep.10, 2018, to U.S. Provisional Patent Application No. 62/729,182, titledSENSING THE PATIENT POSITION AND CONTACT UTILIZING THE MONO-POLAR RETURNPAD ELECTRODE TO PROVIDE SITUATIONAL AWARENESS TO THE HUB, filed Sep.10, 2018, to U.S. Provisional Patent Application No. 62/729,191, titledSURGICAL NETWORK RECOMMENDATIONS FROM REAL TIME ANALYSIS OF PROCEDUREVARIABLES AGAINST A BASELINE HIGHLIGHTING DIFFERENCES FROM THE OPTIMALSOLUTION, filed Sep. 10, 2018, to U.S. Provisional Patent ApplicationNo. 62/729,195, titled ULTRASONIC ENERGY DEVICE WHICH VARIES PRESSUREAPPLIED BY CLAMP ARM TO PROVIDE THRESHOLD CONTROL PRESSURE AT A CUTPROGRESSION LOCATION, filed Sep. 10, 2018, and to U.S. ProvisionalPatent Application No. 62/729,186, titled WIRELESS PAIRING OF A SURGICALDEVICE WITH ANOTHER DEVICE WITHIN A STERILE SURGICAL FIELD BASED ON THEUSAGE AND SITUATIONAL AWARENESS OF DEVICES, filed Sep. 10, 2018, thedisclosure of each of which is herein incorporated by reference in itsentirety.

U.S. patent application Ser. No. 16/209,458 also claims priority under35 U.S.C. § 119(e) to U.S. Provisional Patent Application No.62/721,995, titled CONTROLLING AN ULTRASONIC SURGICAL INSTRUMENTACCORDING TO TISSUE LOCATION, filed Aug. 23, 2018, to U.S. ProvisionalPatent Application No. 62/721,998, titled SITUATIONAL AWARENESS OFELECTROSURGICAL SYSTEMS, filed Aug. 23, 2018, to U.S. Provisional PatentApplication No. 62/721,999, titled INTERRUPTION OF ENERGY DUE TOINADVERTENT CAPACITIVE COUPLING, filed Aug. 23, 2018, to U.S.Provisional Patent Application No. 62/721,994, titled BIPOLARCOMBINATION DEVICE THAT AUTOMATICALLY ADJUSTS PRESSURE BASED ON ENERGYMODALITY, filed Aug. 23, 2018, and to U.S. Provisional PatentApplication No. 62/721,996, titled RADIO FREQUENCY ENERGY DEVICE FORDELIVERING COMBINED ELECTRICAL SIGNALS, filed Aug. 23, 2018, thedisclosure of each of which is herein incorporated by reference in itsentirety.

U.S. patent application Ser. No. 16/209,458 also claims priority under35 U.S.C. § 119(e) to U.S. Provisional Patent Application No.62/692,747, titled SMART ACTIVATION OF AN ENERGY DEVICE BY ANOTHERDEVICE, filed on Jun. 30, 2018, to U.S. Provisional Patent ApplicationNo. 62/692,748, titled SMART ENERGY ARCHITECTURE, filed on Jun. 30,2018, and to U.S. Provisional Patent Application No. 62/692,768, titledSMART ENERGY DEVICES, filed on Jun. 30, 2018, the disclosure of each ofwhich is herein incorporated by reference in its entirety.

U.S. patent application Ser. No. 16/209,458 also claims priority under35 U.S.C. § 119(e) to U.S. Provisional Patent Application No.62/691,228, titled METHOD OF USING REINFORCED FLEX CIRCUITS WITHMULTIPLE SENSORS WITH ELECTROSURGICAL DEVICES, filed Jun. 28, 2018, toU.S. Provisional Patent Application No. 62/691,227, titled CONTROLLING ASURGICAL INSTRUMENT ACCORDING TO SENSED CLOSURE PARAMETERS, filed Jun.28, 2018, to U.S. Provisional Patent Application No. 62/691,230, titledSURGICAL INSTRUMENT HAVING A FLEXIBLE ELECTRODE, filed Jun. 28, 2018, toU.S. Provisional Patent Application No. 62/691,219, titled SURGICALEVACUATION SENSING AND MOTOR CONTROL, filed Jun. 28, 2018, to U.S.Provisional Patent Application No. 62/691,257, titled COMMUNICATION OFSMOKE EVACUATION SYSTEM PARAMETERS TO HUB OR CLOUD IN SMOKE EVACUATIONMODULE FOR INTERACTIVE SURGICAL PLATFORM, filed Jun. 28, 2018, to U.S.Provisional Patent Application No. 62/691,262, titled SURGICALEVACUATION SYSTEM WITH A COMMUNICATION CIRCUIT FOR COMMUNICATION BETWEENA FILTER AND A SMOKE EVACUATION DEVICE, filed Jun. 28, 2018, and to U.S.Provisional Patent Application No. 62/691,251, titled DUAL IN-SERIESLARGE AND SMALL DROPLET FILTERS, filed Jun. 28, 2018, the disclosure ofeach of which is herein incorporated by reference in its entirety.

U.S. patent application Ser. No. 16/209,458 claims priority under 35U.S.C. § 119(e) to U.S. Provisional Patent Application No. 62/665,129,titled SURGICAL SUTURING SYSTEMS, filed May 1, 2018, to U.S. ProvisionalPatent Application No. 62/665,139, titled SURGICAL INSTRUMENTSCOMPRISING CONTROL SYSTEMS, filed May 1, 2018, to U.S. ProvisionalPatent Application No. 62/665,177, titled SURGICAL INSTRUMENTSCOMPRISING HANDLE ARRANGEMENTS, filed May 1, 2018, to U.S. ProvisionalPatent Application No. 62/665,128, titled MODULAR SURGICAL INSTRUMENTS,filed May 1, 2018, to U.S. Provisional Patent Application No.62/665,192, titled SURGICAL DISSECTORS, filed May 1, 2018, and to U.S.Provisional Patent Application No. 62/665,134, titled SURGICAL CLIPAPPLIER, filed May 1, 2018, the disclosure of each of which is hereinincorporated by reference in its entirety.

U.S. patent application Ser. No. 16/209,458 also claims priority under35 U.S.C. § 119(e) to U.S. Provisional Patent Application No.62/659,900, titled METHOD OF HUB COMMUNICATION, filed on Apr. 19, 2018,the disclosure of which is herein incorporated by reference in itsentirety.

U.S. patent application Ser. No. 16/209,458 also claims priority under35 U.S.C. § 119(e) to U.S. Provisional Patent Application No.62/650,898, filed on Mar. 30, 2018, titled CAPACITIVE COUPLED RETURNPATH PAD WITH SEPARABLE ARRAY ELEMENTS, to U.S. Provisional PatentApplication No. 62/650,887, titled SURGICAL SYSTEMS WITH OPTIMIZEDSENSING CAPABILITIES, filed Mar. 30, 2018, to U.S. Provisional PatentApplication No. 62/650,882, titled SMOKE EVACUATION MODULE FORINTERACTIVE SURGICAL PLATFORM, filed Mar. 30, 2018, and to U.S.Provisional Patent Application No. 62/650,877, titled SURGICAL SMOKEEVACUATION SENSING AND CONTROLS, filed Mar. 30, 2018, the disclosure ofeach of which is herein incorporated by reference in its entirety.

U.S. patent application Ser. No. 16/209,458 also claims the benefit ofpriority under 35 U.S.C. § 119(e) to U.S. Provisional Patent ApplicationNo. 62/649,302, titled INTERACTIVE SURGICAL SYSTEMS WITH ENCRYPTEDCOMMUNICATION CAPABILITIES, filed Mar. 28, 2018, to U.S. ProvisionalPatent Application No. 62/649,294, titled DATA STRIPPING METHOD TOINTERROGATE PATIENT RECORDS AND CREATE ANONYMIZED RECORD, filed Mar. 28,2018, to U.S. Provisional Patent Application No. 62/649,300, titledSURGICAL HUB SITUATIONAL AWARENESS, filed Mar. 28, 2018, to U.S.Provisional Patent Application No. 62/649,309, titled SURGICAL HUBSPATIAL AWARENESS TO DETERMINE DEVICES IN OPERATING THEATER, filed Mar.28, 2018, to U.S. Provisional Patent Application No. 62/649,310, titledCOMPUTER IMPLEMENTED INTERACTIVE SURGICAL SYSTEMS, filed Mar. 28, 2018,to U.S. Provisional Patent Application No. 62/649,291, titled USE OFLASER LIGHT AND RED-GREEN-BLUE COLORATION TO DETERMINE PROPERTIES OFBACK SCATTERED LIGHT, filed Mar. 28, 2018, to U.S. Provisional PatentApplication No. 62/649,296, titled ADAPTIVE CONTROL PROGRAM UPDATES FORSURGICAL DEVICES, filed Mar. 28, 2018, to U.S. Provisional PatentApplication No. 62/649,333, titled CLOUD-BASED MEDICAL ANALYTICS FORCUSTOMIZATION AND RECOMMENDATIONS TO A USER, filed Mar. 28, 2018, toU.S. Provisional Patent Application No. 62/649,327, titled CLOUD-BASEDMEDICAL ANALYTICS FOR SECURITY AND AUTHENTICATION TRENDS AND REACTIVEMEASURES, filed Mar. 28, 2018, to U.S. Provisional Patent ApplicationNo. 62/649,315, titled DATA HANDLING AND PRIORITIZATION IN A CLOUDANALYTICS NETWORK, filed Mar. 28, 2018, to U.S. Provisional PatentApplication No. 62/649,313, titled CLOUD INTERFACE FOR COUPLED SURGICALDEVICES, filed Mar. 28, 2018, to U.S. Provisional Patent Application No.62/649,320, titled DRIVE ARRANGEMENTS FOR ROBOT-ASSISTED SURGICALPLATFORMS, filed Mar. 28, 2018, to U.S. Provisional Patent ApplicationNo. 62/649,307, titled AUTOMATIC TOOL ADJUSTMENTS FOR ROBOT-ASSISTEDSURGICAL PLATFORMS, filed Mar. 28, 2018, and to U.S. Provisional PatentApplication No. 62/649,323, titled SENSING ARRANGEMENTS FORROBOT-ASSISTED SURGICAL PLATFORMS, filed Mar. 28, 2018, the disclosureof each of which is herein incorporated by reference in its entirety.

U.S. patent application Ser. No. 16/209,458 also claims the benefit ofpriority under 35 U.S.C. § 119(e) to U.S. Provisional Patent ApplicationNo. 62/611,341, titled INTERACTIVE SURGICAL PLATFORM, filed Dec. 28,2017, to U.S. Provisional Patent Application No. 62/611,340, titledCLOUD-BASED MEDICAL ANALYTICS, filed Dec. 28, 2017, and to U.S.Provisional Patent Application No. 62/611,339, titled ROBOT ASSISTEDSURGICAL PLATFORM, filed Dec. 28, 2017, the disclosure of each of whichis herein incorporated by reference in its entirety.

BACKGROUND

In a surgical environment, smart energy devices may be needed in a smartenergy architecture environment.

SUMMARY

In one aspect the present disclosure provides a method forcharacterizing a state of an end effector of an ultrasonic device. Theultrasonic deice comprising an electromechanical ultrasonic systemdefined by a predetermined resonant frequency. The electromechanicalultrasonic system further comprising an ultrasonic transducer coupled toan ultrasonic blade. The method comprising: applying, by an energysource, a power level to the ultrasonic transducer, measuring, by acontrol circuit coupled to a memory, an impedance value of theultrasonic transducer, comparing, by the control circuit, the impedancevalue to a reference impedance value stored in the memory; classifying,by the control circuit, the impedance value based on the comparison;characterizing, by the control circuit, the state of theelectromechanical ultrasonic system based on the classification of theimpedance value; and adjusting, by the control circuit, the power levelapplied to the ultrasonic transducer based on the characterization ofthe state of the end effector.

In another aspect the present disclosure provides a method forcharacterizing a function of an end effector of an ultrasonic device.The ultrasonic deice comprising an electromechanical ultrasonic systemdefined by a predetermined resonant frequency. The electromechanicalultrasonic system further comprising an ultrasonic transducer coupled toan ultrasonic blade. The method comprising: applying, by an energysource, a power level to the ultrasonic transducer, measuring, by acontrol circuit coupled to a memory, an impedance value of theultrasonic transducer, comparing, by the control circuit, the impedancevalue to a reference impedance value stored in the memory; classifying,by the control circuit, the impedance value based on the comparison;characterizing, by the control circuit, the function of theelectromechanical ultrasonic system based on the classification of theimpedance value; and adjusting, by the control circuit, the power levelapplied to the ultrasonic transducer based on the characterization ofthe function of the end effector.

In another aspect the present disclosure provides a method forcharacterizing a tissue in contact with an end effector of an ultrasonicdevice. The ultrasonic deice comprising an electromechanical ultrasonicsystem defined by a predetermined resonant frequency. Theelectromechanical ultrasonic system further comprising an ultrasonictransducer coupled to an ultrasonic blade. The method comprising:applying, by an energy source, a power level to the ultrasonictransducer, measuring, by a control circuit coupled to a memory, animpedance value of the ultrasonic transducer, comparing, by the controlcircuit, the impedance value to a reference impedance value stored inthe memory; classifying, by the control circuit, the impedance valuebased on the comparison; characterizing, by the control circuit, thetissue in contact with the end effector based on the classification ofthe impedance value; and adjusting, by the control circuit, the powerlevel applied to the ultrasonic transducer based on the characterizationof the tissue in contact with the end effector.

FIGURES

The features of various aspects are set forth with particularity in theappended claims. The various aspects, however, both as to organizationand methods of operation, together with further objects and advantagesthereof, may best be understood by reference to the followingdescription, taken in conjunction with the accompanying drawings asfollows.

FIG. 1 is a block diagram of a computer-implemented interactive surgicalsystem, in accordance with at least one aspect of the presentdisclosure.

FIG. 2 is a surgical system being used to perform a surgical procedurein an operating room, in accordance with at least one aspect of thepresent disclosure.

FIG. 3 is a surgical hub paired with a visualization system, a roboticsystem, and an intelligent instrument, in accordance with at least oneaspect of the present disclosure.

FIG. 4 is a partial perspective view of a surgical hub enclosure, and ofa combo generator module slidably receivable in a drawer of the surgicalhub enclosure, in accordance with at least one aspect of the presentdisclosure.

FIG. 5 is a perspective view of a combo generator module with bipolar,ultrasonic, and monopolar contacts and a smoke evacuation component, inaccordance with at least one aspect of the present disclosure.

FIG. 6 illustrates individual power bus attachments for a plurality oflateral docking ports of a lateral modular housing configured to receivea plurality of modules, in accordance with at least one aspect of thepresent disclosure.

FIG. 7 illustrates a vertical modular housing configured to receive aplurality of modules, in accordance with at least one aspect of thepresent disclosure.

FIG. 8 illustrates a surgical data network comprising a modularcommunication hub configured to connect modular devices located in oneor more operating theaters of a healthcare facility, or any room in ahealthcare facility specially equipped for surgical operations, to thecloud, in accordance with at least one aspect of the present disclosure.

FIG. 9 illustrates a computer-implemented interactive surgical system,in accordance with at least one aspect of the present disclosure.

FIG. 10 illustrates a surgical hub comprising a plurality of modulescoupled to the modular control tower, in accordance with at least oneaspect of the present disclosure.

FIG. 11 illustrates one aspect of a Universal Serial Bus (USB) networkhub device, in accordance with at least one aspect of the presentdisclosure.

FIG. 12 illustrates a logic diagram of a control system of a surgicalinstrument or tool, in accordance with at least one aspect of thepresent disclosure.

FIG. 13 illustrates a control circuit configured to control aspects ofthe surgical instrument or tool, in accordance with at least one aspectof the present disclosure.

FIG. 14 illustrates a combinational logic circuit configured to controlaspects of the surgical instrument or tool, in accordance with at leastone aspect of the present disclosure.

FIG. 15 illustrates a sequential logic circuit configured to controlaspects of the surgical instrument or tool, in accordance with at leastone aspect of the present disclosure.

FIG. 16 illustrates a surgical instrument or tool comprising a pluralityof motors which can be activated to perform various functions, inaccordance with at least one aspect of the present disclosure.

FIG. 17 is a schematic diagram of a robotic surgical instrumentconfigured to operate a surgical tool described herein, in accordancewith at least one aspect of the present disclosure.

FIG. 18 illustrates a block diagram of a surgical instrument programmedto control the distal translation of a displacement member, inaccordance with at least one aspect of the present disclosure.

FIG. 19 is a schematic diagram of a surgical instrument configured tocontrol various functions, in accordance with at least one aspect of thepresent disclosure.

FIG. 20 is a system configured to execute adaptive ultrasonic bladecontrol algorithms in a surgical data network comprising a modularcommunication hub, in accordance with at least one aspect of the presentdisclosure.

FIG. 21 illustrates an example of a generator, in accordance with atleast one aspect of the present disclosure.

FIG. 22 is a surgical system comprising a generator and various surgicalinstruments usable therewith, in accordance with at least one aspect ofthe present disclosure.

FIG. 23 is an end effector, in accordance with at least one aspect ofthe present disclosure.

FIG. 24 is a diagram of the surgical system of FIG. 22 , in accordancewith at least one aspect of the present disclosure.

FIG. 25 is a model illustrating motional branch current, in accordancewith at least one aspect of the present disclosure.

FIG. 26 is a structural view of a generator architecture, in accordancewith at least one aspect of the present disclosure.

FIGS. 27A-27C are functional views of a generator architecture, inaccordance with at least one aspect of the present disclosure.

FIGS. 28A-28B are structural and functional aspects of a generator, inaccordance with at least one aspect of the present disclosure.

FIG. 29 is a schematic diagram of one aspect of an ultrasonic drivecircuit.

FIG. 30 is a schematic diagram of the transformer coupled to theultrasonic drive circuit shown in FIG. 29 , in accordance with at leastone aspect of the present disclosure.

FIG. 31 is a schematic diagram of the transformer shown in FIG. 30coupled to a test circuit, in accordance with at least one aspect of thepresent disclosure.

FIG. 32 is a schematic diagram of a control circuit, in accordance withat least one aspect of the present disclosure.

FIG. 33 shows a simplified block circuit diagram illustrating anotherelectrical circuit contained within a modular ultrasonic surgicalinstrument, in accordance with at least one aspect of the presentdisclosure.

FIG. 34 illustrates a generator circuit partitioned into multiplestages, in accordance with at least one aspect of the presentdisclosure.

FIG. 35 illustrates a generator circuit partitioned into multiple stageswhere a first stage circuit is common to the second stage circuit, inaccordance with at least one aspect of the present disclosure.

FIG. 36 is a schematic diagram of one aspect of a drive circuitconfigured for driving a high-frequency current (RF), in accordance withat least one aspect of the present disclosure.

FIG. 37 is a schematic diagram of the transformer coupled to the RFdrive circuit shown in FIG. 34 , in accordance with at least one aspectof the present disclosure.

FIG. 38 is a schematic diagram of a circuit comprising separate powersources for high power energy/drive circuits and low power circuits,according to one aspect of the resent disclosure.

FIG. 39 illustrates a control circuit that allows a dual generatorsystem to switch between the RF generator and the ultrasonic generatorenergy modalities for a surgical instrument.

FIG. 40 illustrates a diagram of one aspect of a surgical instrumentcomprising a feedback system for use with a surgical instrument,according to one aspect of the present disclosure.

FIG. 41 illustrates one aspect of a fundamental architecture for adigital synthesis circuit such as a direct digital synthesis (DDS)circuit configured to generate a plurality of wave shapes for theelectrical signal waveform for use in a surgical instrument, inaccordance with at least one aspect of the present disclosure.

FIG. 42 illustrates one aspect of direct digital synthesis (DDS) circuitconfigured to generate a plurality of wave shapes for the electricalsignal waveform for use in surgical instrument, in accordance with atleast one aspect of the present disclosure.

FIG. 43 illustrates one cycle of a discrete time digital electricalsignal waveform, in accordance with at least one aspect of the presentdisclosure of an analog waveform (shown superimposed over a discretetime digital electrical signal waveform for comparison purposes), inaccordance with at least one aspect of the present disclosure.

FIG. 44 is a diagram of a control system configured to provideprogressive closure of a closure member as it advances distally to closethe clamp arm to apply a closure force load at a desired rate accordingto one aspect of this disclosure.

FIG. 45 illustrates a proportional-integral-derivative (PID) controllerfeedback control system according to one aspect of this disclosure.

FIG. 46 is an elevational exploded view of modular handheld ultrasonicsurgical instrument showing the left shell half removed from a handleassembly exposing a device identifier communicatively coupled to themulti-lead handle terminal assembly in accordance with one aspect of thepresent disclosure.

FIG. 47 is a detail view of a trigger portion and switch of theultrasonic surgical instrument shown in FIG. 46 , in accordance with atleast one aspect of the present disclosure.

FIG. 48 is a fragmentary, enlarged perspective view of an end effectorfrom a distal end with a jaw member in an open position, in accordancewith at least one aspect of the present disclosure.

FIG. 49 is a system diagram of a segmented circuit comprising aplurality of independently operated circuit segments, in accordance withat least one aspect of the present disclosure.

FIG. 50 is a circuit diagram of various components of a surgicalinstrument with motor control functions, in accordance with at least oneaspect of the present disclosure.

FIG. 51 illustrates one aspect of an end effector comprising RF datasensors located on the jaw member, in accordance with at least oneaspect of the present disclosure.

FIG. 52 illustrates one aspect of the flexible circuit shown in FIG. 51in which the sensors may be mounted to or formed integrally therewith,in accordance with at least one aspect of the present disclosure.

FIG. 53 is an alternative system for controlling the frequency of anultrasonic electromechanical system and detecting the impedance thereof,in accordance with at least one aspect of the present disclosure.

FIG. 54 is a spectra of the same ultrasonic device with a variety ofdifferent states and conditions of the end effector where phase andmagnitude of the impedance of an ultrasonic transducer are plotted as afunction of frequency, in accordance with at least one aspect of thepresent disclosure.

FIG. 55 is a graphical representation of a plot of a set of 3D trainingdata S, where ultrasonic transducer impedance magnitude and phase areplotted as a function of frequency, in accordance with at least oneaspect of the present disclosure.

FIG. 56 is a logic flow diagram depicting a control program or a logicconfiguration to determine jaw conditions based on the complex impedancecharacteristic pattern (fingerprint), in accordance with at least oneaspect of the present disclosure.

FIG. 57 is a circle plot of complex impedance plotted as an imaginarycomponent versus real components of a piezoelectric vibrator, inaccordance with at least one aspect of the present disclosure.

FIG. 58 is a circle plot of complex admittance plotted as an imaginarycomponent versus real components of a piezoelectric vibrator, inaccordance with at least one aspect of the present disclosure.

FIG. 59 is a circle plot of complex admittance for a 55.5 kHz ultrasonicpiezoelectric transducer.

FIG. 60 is a graphical display of an impedance analyzer showingimpedance/admittance circle plots for an ultrasonic device with the jawopen and no loading where red depicts admittance and blue depictsimpedance, in accordance with at least one aspect of the presentdisclosure.

FIG. 61 is a graphical display of an impedance analyzer showingimpedance/admittance circle plots for an ultrasonic device with the jawclamped on dry chamois where red depicts admittance and blue depictsimpedance, in accordance with at least one aspect of the presentdisclosure.

FIG. 62 is a graphical display of an impedance analyzer showingimpedance/admittance circle plots for an ultrasonic device with the jawtip clamped on moist chamois where red depicts admittance and bluedepicts impedance, in accordance with at least one aspect of the presentdisclosure.

FIG. 63 is a graphical display of an impedance analyzer showingimpedance/admittance circle plots for an ultrasonic device with the jawfully clamped on moist chamois where red depicts admittance and bluedepicts impedance, in accordance with at least one aspect of the presentdisclosure.

FIG. 64 is a graphical display of an impedance analyzer showingimpedance/admittance plots where frequency is swept from 48 kHz to 62kHz to capture multiple resonances of an ultrasonic device with the jawopen where the gray overlay is to help see the circles, in accordancewith at least one aspect of the present disclosure.

FIG. 65 is a logic flow diagram of a process depicting a control programor a logic configuration to determine jaw conditions based on estimatesof the radius and offsets of an impedance/admittance circle, inaccordance with at least one aspect of the present disclosure.

FIGS. 66A-66B are graphical representations of an ultrasonic transducercurrent hemostasis algorithm, where

FIG. 66A is a graphical representation of percent of maximum currentinto an ultrasonic transducer as a function of time and

FIG. 66B is a graphical representation of ultrasonic blade temperatureas a function of time and tissue type, in accordance with at least oneaspect of the present disclosure.

FIG. 67 is a logic flow diagram of a process depicting a control programor a logic configuration to control the temperature of an ultrasonicblade based on tissue type, in accordance with at least one aspect ofthe present disclosure.

FIG. 68 is a logic flow diagram of a process depicting a control programor a logic configuration to monitor the impedance of an ultrasonictransducer to profile an ultrasonic blade and deliver power to theultrasonic blade on the profile according to one aspect of the resentdisclosure.

FIGS. 69A-69D is a series of graphical representations monitoring theimpedance of an ultrasonic transducer to profile an ultrasonic blade anddeliver power to the ultrasonic blade on the profile according to oneaspect of the resent disclosure, where

FIG. 69A is a graphical representation of the initial impedance of theultrasonic transducer as a function of time,

FIG. 69B is a graphical representation of power delivered to theultrasonic blade as a function of time based on the initial impedance,

FIG. 69C is a graphical representation of a new impedance of theultrasonic transducer as a function of time, and

FIG. 69D is a graphical representation of adjusted power delivered tothe ultrasonic blade based on the new impedance.

FIG. 70 is a system for adjusting complex impedance of the ultrasonictransducer to compensate for power lost when the ultrasonic blade isarticulated, in accordance with at least one aspect of the presentdisclosure.

FIG. 71 is a logic flow diagram of a process depicting a control programor a logic configuration to compensate output power as a function ofarticulation angle, in accordance with at least one aspect of thepresent disclosure.

FIG. 72 is system for measuring complex impedance of an ultrasonictransducer in real time to determine action being performed by anultrasonic blade, in accordance with at least one aspect of the presentdisclosure.

FIG. 73 is a logic flow diagram of a process depicting a control programor a logic configuration to determine action being performed by theultrasonic blade based on the complex impedance pattern, in accordancewith at least one aspect of the present disclosure.

FIG. 74 is a logic flow diagram depicting a control program or a logicconfiguration of an adaptive process for identifying a hemostasisvessel, in accordance with at least one aspect of the presentdisclosure.

FIG. 75 is a graphical representation of ultrasonic transducer currentprofiles as a function of time for vein and artery vessel types, inaccordance with at least one aspect of the present disclosure.

FIG. 76 is a logic flow diagram depicting a control program or a logicconfiguration of an adaptive process for identifying a hemostasisvessel, in accordance with at least one aspect of the presentdisclosure.

FIG. 77 is a graphical representation of ultrasonic transducer frequencyprofiles as a function of time for vein and artery vessel types, inaccordance with at least one aspect of the present disclosure.

FIG. 78 is a logic flow diagram depicting a control program or a logicconfiguration of a process for identifying a calcified vessel, inaccordance with at least one aspect of the present disclosure.

FIG. 79 is a logic flow diagram depicting a control program or a logicconfiguration of a process for identifying a calcified vessel, inaccordance with at least one aspect of the present disclosure.

FIG. 80 is a logic flow diagram depicting a control program or a logicconfiguration of a process for identifying a calcified vessel, inaccordance with at least one aspect of the present disclosure.

FIG. 81 is a diagram of a liver resection with vessels embedded inparenchymal tissue, in accordance with at least one aspect of thepresent disclosure.

FIG. 82 is a diagram of an ultrasonic blade in parenchyma but notcontacting a vessel, in accordance with at least one aspect of thepresent disclosure.

FIGS. 83A-83B are ultrasonic transducer impedance magnitude/phase plotswith curves for parenchyma shown inbold line, in accordance with atleast one aspect of the present disclosure.

FIG. 84 is a diagram of an ultrasonic blade in parenchyma and contactinga large vessel.

FIGS. 85A-85B are ultrasonic transducer impedance magnitude/phase plotswith curves for a large vessel shown inbold line, in accordance with atleast one aspect of the present disclosure.

FIG. 86 is a logic flow diagram depicting a control program or a logicconfiguration of a process for treating tissue in parenchyma when avessel is detected, in accordance with at least one aspect of thepresent disclosure.

FIG. 87 is an ultrasonic device configured to identify the status of theultrasonic blade and determine the clocked clamp arm status to determinewhether a disposable portion of a reusable and disposable ultrasonicdevice has been installed correctly, in accordance with at least oneaspect of the present disclosure.

FIG. 88 is an end effector portion of the ultrasonic device shown inFIG. 52 .

FIG. 89 is an ultrasonic device configured to identify the status of theultrasonic blade and determine whether the clamp arm is not completelydistal to determine whether a disposable portion of a reusable anddisposable ultrasonic device has been installed correctly, in accordancewith at least one aspect of the present disclosure.

FIG. 90 is a logic flow diagram depicting a control program or a logicconfiguration to identify the status of components of reusable anddisposable devices, in accordance with at least one aspect of thepresent disclosure.

FIG. 91 is a three-dimensional graphical representation of tissue radiofrequency (RF) impedance classification, in accordance with at least oneaspect of the present disclosure.

FIG. 92 is a three-dimensional graphical representation of tissue radiofrequency (RF) impedance analysis, in accordance with at least oneaspect of the present disclosure.

FIG. 93 is a graphical representation of carotid technique sensitivitywhere the time impedance (Z) derivative is plotted as a function ofinitial radio frequency (RF) impedance, in accordance with at least oneaspect of the present disclosure.

FIG. 94A is a graphical representation of impedance phase angle as afunction of resonant frequency of the same ultrasonic device with a cold(solid line) and hot (broken line) ultrasonic blade; and

FIG. 94B is a graphical representation of impedance magnitude as afunction of resonant frequency of the same ultrasonic device with a cold(solid line) and hot (broken line) ultrasonic blade.

FIG. 95 is a diagram of a Kalman filter to improve temperature estimatorand state space model based on impedance across an ultrasonic transducermeasured at a variety of frequencies, in accordance with at least oneaspect of the present disclosure.

FIG. 96 are three probability distributions employed by a stateestimator of the Kalman filter shown in FIG. 95 to maximize estimates,in accordance with at least one aspect of the present disclosure.

FIG. 97A is a graphical representation of temperature versus time of anultrasonic device with no temperature control reaching a maximumtemperature of 490° C.

FIG. 97B is a graphical representation of temperature versus time of anultrasonic device with temperature control reaching a maximumtemperature of 320° C., in accordance with at least one aspect of thepresent disclosure.

FIG. 98 is a graphical representation of the relationship betweeninitial frequency and the change in frequency required to achieve atemperature of approximately 340° C., in accordance with at least oneaspect of the present disclosure.

FIG. 99 illustrates a feedback control system comprising an ultrasonicgenerator to regulate the electrical current (i) set point applied to anultrasonic transducer of an ultrasonic electromechanical system toprevent the frequency (f) of the ultrasonic transducer from decreasinglower than a predetermined threshold, in accordance with at least oneaspect of the present disclosure.

FIG. 100 is a logic flow diagram of a process depicting a controlprogram or a logic configuration of a controlled thermal managementprocess to protect an end effector pad, in accordance with at least oneaspect of the present disclosure.

FIG. 101 is a graphical representation of temperature versus timecomparing the desired temperature of an ultrasonic blade with a smartultrasonic blade and a conventional ultrasonic blade, in accordance withat least one aspect of the present disclosure.

FIGS. 102A-102B are graphical representations of feedback control toadjust ultrasonic power applied to an ultrasonic transducer when asudden drop in temperature of an ultrasonic blade is detected, where

FIG. 102A is a graphical representation of ultrasonic power as afunction of time; and

FIG. 102B is a plot of ultrasonic blade temperature as a function oftime, in accordance with at least one aspect of the present disclosure.

FIG. 103 is a logic flow diagram of a process depicting a controlprogram or a logic configuration to control the temperature of anultrasonic blade, in accordance with at least one aspect of the presentdisclosure.

FIG. 104 is a graphical representation of ultrasonic blade temperatureas a function of time during a vessel firing, in accordance with atleast one aspect of the present disclosure.

FIG. 105 is a logic flow diagram of a process depicting a controlprogram or a logic configuration to control the temperature of anultrasonic blade between two temperature set points, in accordance withat least one aspect of the present disclosure.

FIG. 106 is a logic flow diagram of a process depicting a controlprogram or a logic configuration to determine the initial temperature ofan ultrasonic blade, in accordance with at least one aspect of thepresent disclosure.

FIG. 107 is a logic flow diagram of a process depicting a controlprogram or a logic configuration to determine when an ultrasonic bladeis approaching instability and then adjusting the power to theultrasonic transducer to prevent instability of the ultrasonictransducer, in accordance with at least one aspect of the presentdisclosure.

FIG. 108 is a logic flow diagram of a process depicting a controlprogram or a logic configuration to provide ultrasonic sealing withtemperature control, in accordance with at least one aspect of thepresent disclosure.

FIG. 109 are graphical representations of ultrasonic transducer currentand ultrasonic blade temperature as a function of time, in accordancewith at least one aspect of the present disclosure.

FIG. 110 provides a diagram showing an example system with means fordetecting capacitive coupling, in accordance with at least one aspect ofthe present disclosure.

FIG. 111 is a logic flow diagram depicting a control program or a logicconfiguration of an example methodology for limiting the effects ofcapacitive coupling in a surgical system is disclosed, in accordancewith at least one aspect of the present disclosure.

FIG. 112 is a logic flow diagram depicting a control program or a logicconfiguration of an example methodology that may be performed by thesurgical system utilizing monopolar energy generation to determinewhether to take advantage of parasitic capacitive coupling, inaccordance with at least one aspect of the present disclosure.

FIG. 113 is a logic flow diagram depicting a control program or a logicconfiguration to adjust compression force applied to tissue, based onone or more selected energy modalities, according to a least one aspectof the present disclosure.

FIG. 114 illustrates a mechanical method of adjusting compression forceapplied by an end effector for different treatment types, in accordancewith at least one aspect of the present disclosure.

FIGS. 115A-115B illustrate a mechanical method of adjusting compressionforce applied by an end effector for different treatment types, byrotating an ultrasonic blade, in accordance with at least one aspect ofthe present disclosure.

FIG. 116 shows a diagram illustrating switching between activeelectrodes of an end effector, in accordance with at least one aspect ofthe present disclosure.

FIG. 117 depicts a surgical procedure using an electrosurgical system inaccordance with at least one aspect of the present disclosure.

FIG. 118 illustrates a block diagram of the electrosurgical system usedin FIG. 117 in accordance with at least one aspect of the presentdisclosure.

FIG. 119 illustrates a return pad of the electrosurgical system of FIG.117 including a plurality of electrodes in accordance with at least oneaspect of the present disclosure.

FIG. 120 illustrates an array of sensing devices in the return paddepicted in FIG. 118 in accordance with at least one aspect of thepresent disclosure.

FIG. 121 is a graphical representation of a therapeutic RF signal thatmay be used in an electrosurgical system in accordance with at least oneaspect of the present disclosure.

FIG. 122 is a graphical representation of a nerve stimulation signalthat may be incorporated in an electrosurgical system in accordance withat least one aspect of the present disclosure.

FIGS. 123A-123C are graphical representations of signals used by anelectrosurgical system that may incorporate features of both thetherapeutic RF signal of FIG. 121 and the nerve stimulation signal ofFIG. 122 in accordance with at least one aspect of the presentdisclosure.

FIG. 124 summarizes a method in which such a control for a smartelectrosurgical device may be effected in accordance with at least oneaspect of the present disclosure.

FIG. 125 illustrates an ultrasonic surgical instrument system, inaccordance with at least one aspect of the present disclosure.

FIGS. 126A-126C illustrate a piezoelectric transducer, in accordancewith at least one aspect of the present disclosure.

FIG. 127 illustrates a D31 ultrasonic transducer architecture thatincludes an ultrasonic waveguide and one or more piezoelectric elementsfixed to the ultrasonic waveguide, in accordance with at least oneaspect of the present disclosure.

FIG. 128 illustrates a cutaway view of an ultrasonic surgicalinstrument, in accordance with at least one aspect of the presentdisclosure.

FIG. 129 illustrates an exploded view of the ultrasonic surgicalinstrument in FIG. 128 , in accordance with at least one aspect of thepresent disclosure.

FIG. 130 illustrates a block diagram of a surgical system, in accordancewith at least one aspect of the present disclosure.

FIG. 131 illustrates a perspective view of a surgical instrumentincluding a sensor assembly configured to detect a user-worn magneticreference, in accordance with at least one aspect of the presentdisclosure.

FIG. 132A illustrates a sectional view along line 131-131 of a surgicalinstrument including a sensor assembly configured to detect an integralmagnetic reference, in accordance with at least one aspect of thepresent disclosure.

FIG. 132B illustrates a detail view of the surgical instrument of FIG.132A in a first position, in accordance with at least one aspect of thepresent disclosure.

FIG. 132C illustrates a detail view of the surgical instrument of FIG.132A in a second position, in accordance with at least one aspect of thepresent disclosure.

FIG. 133A illustrates a perspective view of a surgical instrumentincluding a sensor assembly configured to detect contact thereagainstthat is oriented orthogonally, in accordance with at least one aspect ofthe present disclosure.

FIG. 133B illustrates a perspective view of a surgical instrumentincluding a sensor assembly configured to detect contact thereagainstthat is oriented laterally, in accordance with at least one aspect ofthe present disclosure.

FIG. 134 illustrates a circuit diagram of the surgical instrument ofeither FIG. 133A or FIG. 133B, in accordance with at least one aspect ofthe present disclosure.

FIG. 135A illustrates a perspective view of a surgical instrumentincluding a sensor assembly configured to detect closure of the surgicalinstrument, wherein the surgical instrument is in an open position, inaccordance with at least one aspect of the present disclosure.

FIG. 135B illustrates a perspective view of a surgical instrumentincluding a sensor assembly configured to detect closure of the surgicalinstrument, wherein the surgical instrument is in a first closedposition, in accordance with at least one aspect of the presentdisclosure.

FIG. 135C illustrates a perspective view of a surgical instrumentincluding a sensor assembly configured to detect closure of the surgicalinstrument, wherein the surgical instrument is in a second closedposition, in accordance with at least one aspect of the presentdisclosure.

FIG. 136A illustrates a perspective view of a surgical instrumentincluding a sensor assembly configured to detect opening of the surgicalinstrument, in accordance with at least one aspect of the presentdisclosure.

FIG. 136B illustrates a sectional view along line 135B-135B of thesurgical instrument of FIG. 136A, in accordance with at least one aspectof the present disclosure.

FIG. 136C illustrates an exploded perspective view of the surgicalinstrument of FIG. 136A, in accordance with at least one aspect of thepresent disclosure.

FIG. 136D illustrates a perspective view of the surgical instrument ofFIG. 136A, in accordance with at least one aspect of the presentdisclosure.

FIG. 136E illustrates a detail view of a portion of FIG. 136D, inaccordance with at least one aspect of the present disclosure.

FIG. 136F illustrates a perspective view of the interior face of the armof the surgical instrument of FIG. 136A, in accordance with at least oneaspect of the present disclosure.

FIG. 137 illustrates a perspective view of a surgical instrumentincluding a sensor assembly comprising a pair of sensors for controllingthe activation of the surgical instrument, in accordance with at leastone aspect of the present disclosure.

FIG. 138 illustrates a perspective view of a surgical instrumentcomprising a deactivation switch, in accordance with at least one aspectof the present disclosure.

FIG. 139 illustrates a perspective view of a retractor comprising asensor, in accordance with at least one aspect of the presentdisclosure.

FIG. 140 illustrates a perspective view of a retractor comprising adisplay in use at a surgical site, in accordance with at least oneaspect of the present disclosure.

FIG. 141 is a timeline depicting situational awareness of a surgicalhub, in accordance with at least one aspect of the present disclosure.

DESCRIPTION

Applicant of the present application owns the following U.S. patentapplications, filed on Dec. 4, 2018, the disclosure of each of which isherein incorporated by reference in its entirety:

-   -   U.S. patent application Ser. No. 16/209,385, titled METHOD OF        HUB COMMUNICATION, PROCESSING, STORAGE AND DISPLAY, now U.S.        Patent Application Publication No. 2019/0200844;    -   U.S. patent application Ser. No. 16/209,395, titled METHOD OF        HUB COMMUNICATION, now U.S.

Patent Application Publication No. 2019/0201136;

-   -   U.S. patent application Ser. No. 16/209,403, titled METHOD OF        CLOUD BASED DATA ANALYTICS FOR USE WITH THE HUB, now U.S. Patent        Application Publication No. 2019/0206569;    -   U.S. patent application Ser. No. 16/209,407, titled METHOD OF        ROBOTIC HUB COMMUNICATION, DETECTION, AND CONTROL, now U.S.        Patent Application Publication No. 2019/0201137;    -   U.S. patent application Ser. No. 16/209,416, titled METHOD OF        HUB COMMUNICATION, PROCESSING, DISPLAY, AND CLOUD ANALYTICS, now        U.S. Patent Application Publication No. 2019/0206562;    -   U.S. patent application Ser. No. 16/209,423, titled METHOD OF        COMPRESSING TISSUE WITHIN A STAPLING DEVICE AND SIMULTANEOUSLY        DISPLAYING THE LOCATION OF THE TISSUE WITHIN THE JAWS, now U.S.        Patent Application Publication No. 2019/0200981;    -   U.S. patent application Ser. No. 16/209,427, titled METHOD OF        USING REINFORCED FLEXIBLE CIRCUITS WITH MULTIPLE SENSORS TO        OPTIMIZE PERFORMANCE OF RADIO FREQUENCY DEVICES, now U.S. Patent        Application Publication No. 2019/0208641;    -   U.S. patent application Ser. No. 16/209,433, titled METHOD OF        SENSING PARTICULATE FROM SMOKE EVACUATED FROM A PATIENT,        ADJUSTING THE PUMP SPEED BASED ON THE SENSED INFORMATION, AND        COMMUNICATING THE FUNCTIONAL PARAMETERS OF THE SYSTEM TO THE        HUB, now U.S. Patent Application Publication No. 2019/0201594;    -   U.S. patent application Ser. No. 16/209,447, titled METHOD FOR        SMOKE EVACUATION FOR SURGICAL HUB, now U.S. Patent Application        Publication No. 2019/0201045;    -   U.S. patent application Ser. No. 16/209,453, titled METHOD FOR        CONTROLLING SMART ENERGY DEVICES, now U.S. Patent Application        Publication No. 2019/0201046;    -   U.S. patent application Ser. No. 16/209,465, titled METHOD FOR        ADAPTIVE CONTROL SCHEMES FOR SURGICAL NETWORK CONTROL AND        INTERACTION, now U.S. Pat. No. 11,304,465;    -   U.S. patent application Ser. No. 16/209,478, titled METHOD FOR        SITUATIONAL AWARENESS FOR SURGICAL NETWORK OR SURGICAL NETWORK        CONNECTED DEVICE CAPABLE OF ADJUSTING FUNCTION BASED ON A SENSED        SITUATION OR USAGE, now U.S. Patent Application Publication No.        2019/0104919;    -   U.S. patent application Ser. No. 16/209,490, titled METHOD FOR        FACILITY DATA COLLECTION AND INTERPRETATION, now U.S. Patent        Application Publication No. 2019/0206564; and    -   U.S. patent application Ser. No. 16/209,491, titled METHOD FOR        CIRCULAR STAPLER CONTROL ALGORITHM ADJUSTMENT BASED ON        SITUATIONAL AWARENESS, now U.S. Pat. No. 11,109,866.

Applicant of the present application owns the following U.S. patentapplications, filed on Nov. 6, 2018, the disclosure of each of which isherein incorporated by reference in its entirety:

-   -   U.S. patent application Ser. No. 16/182,224, titled SURGICAL        NETWORK, INSTRUMENT, AND CLOUD RESPONSES BASED ON VALIDATION OF        RECEIVED DATASET AND AUTHENTICATION OF ITS SOURCE AND INTEGRITY;    -   U.S. patent application Ser. No. 16/182,230, titled SURGICAL        SYSTEM FOR PRESENTING INFORMATION INTERPRETED FROM EXTERNAL        DATA;    -   U.S. patent application Ser. No. 16/182,233, titled SURGICAL        SYSTEMS WITH AUTONOMOUSLY ADJUSTABLE CONTROL PROGRAMS;    -   U.S. patent application Ser. No. 16/182,239, titled ADJUSTMENT        OF DEVICE CONTROL PROGRAMS BASED ON STRATIFIED CONTEXTUAL DATA        IN ADDITION TO THE DATA;    -   U.S. patent application Ser. No. 16/182,243, titled SURGICAL HUB        AND MODULAR DEVICE RESPONSE ADJUSTMENT BASED ON SITUATIONAL        AWARENESS;    -   U.S. patent application Ser. No. 16/182,248, titled DETECTION        AND ESCALATION OF SECURITY RESPONSES OF SURGICAL INSTRUMENTS TO        INCREASING SEVERITY THREATS;    -   U.S. patent application Ser. No. 16/182,251, titled INTERACTIVE        SURGICAL SYSTEM;    -   U.S. patent application Ser. No. 16/182,260, titled AUTOMATED        DATA SCALING, ALIGNMENT, AND ORGANIZING BASED ON PREDEFINED        PARAMETERS WITHIN SURGICAL NETWORKS;    -   U.S. patent application Ser. No. 16/182,267, titled SENSING THE        PATIENT POSITION AND CONTACT UTILIZING THE MONO-POLAR RETURN PAD        ELECTRODE TO PROVIDE SITUATIONAL AWARENESS TO THE HUB;    -   U.S. patent application Ser. No. 16/182,249, titled POWERED        SURGICAL TOOL WITH PREDEFINED ADJUSTABLE CONTROL ALGORITHM FOR        CONTROLLING END EFFECTOR PARAMETER;    -   U.S. patent application Ser. No. 16/182,246, titled ADJUSTMENTS        BASED ON AIRBORNE PARTICLE PROPERTIES;    -   U.S. patent application Ser. No. 16/182,256, titled ADJUSTMENT        OF A SURGICAL DEVICE FUNCTION BASED ON SITUATIONAL AWARENESS;    -   U.S. patent application Ser. No. 16/182,242, titled REAL-TIME        ANALYSIS OF COMPREHENSIVE COST OF ALL INSTRUMENTATION USED IN        SURGERY UTILIZING DATA FLUIDITY TO TRACK INSTRUMENTS THROUGH        STOCKING AND IN-HOUSE PROCESSES;    -   U.S. patent application Ser. No. 16/182,255, titled USAGE AND        TECHNIQUE ANALYSIS OF SURGEON/STAFF PERFORMANCE AGAINST A        BASELINE TO OPTIMIZE DEVICE UTILIZATION AND PERFORMANCE FOR BOTH        CURRENT AND FUTURE PROCEDURES;    -   U.S. patent application Ser. No. 16/182,269, titled IMAGE        CAPTURING OF THE AREAS OUTSIDE THE ABDOMEN TO IMPROVE PLACEMENT        AND CONTROL OF A SURGICAL DEVICE IN USE;    -   U.S. patent application Ser. No. 16/182,278, titled        COMMUNICATION OF DATA WHERE A SURGICAL NETWORK IS USING CONTEXT        OF THE DATA AND REQUIREMENTS OF A RECEIVING SYSTEM/USER TO        INFLUENCE INCLUSION OR LINKAGE OF DATA AND METADATA TO ESTABLISH        CONTINUITY;    -   U.S. patent application Ser. No. 16/182,290, titled SURGICAL        NETWORK RECOMMENDATIONS FROM REAL TIME ANALYSIS OF PROCEDURE        VARIABLES AGAINST A BASELINE HIGHLIGHTING DIFFERENCES FROM THE        OPTIMAL SOLUTION;    -   U.S. patent application Ser. No. 16/182,232, titled CONTROL OF A        SURGICAL SYSTEM THROUGH A SURGICAL BARRIER;    -   U.S. patent application Ser. No. 16/182,227, titled SURGICAL        NETWORK DETERMINATION OF PRIORITIZATION OF COMMUNICATION,        INTERACTION, OR PROCESSING BASED ON SYSTEM OR DEVICE NEEDS;    -   U.S. patent application Ser. No. 16/182,231, titled WIRELESS        PAIRING OF A SURGICAL DEVICE WITH ANOTHER DEVICE WITHIN A        STERILE SURGICAL FIELD BASED ON THE USAGE AND SITUATIONAL        AWARENESS OF DEVICES;    -   U.S. patent application Ser. No. 16/182,229, titled ADJUSTMENT        OF STAPLE HEIGHT OF AT LEAST ONE ROW OF STAPLES BASED ON THE        SENSED TISSUE THICKNESS OR FORCE IN CLOSING;    -   U.S. patent application Ser. No. 16/182,234, titled STAPLING        DEVICE WITH BOTH COMPULSORY AND DISCRETIONARY LOCKOUTS BASED ON        SENSED PARAMETERS;    -   U.S. patent application Ser. No. 16/182,240, titled POWERED        STAPLING DEVICE CONFIGURED TO ADJUST FORCE, ADVANCEMENT SPEED,        AND OVERALL STROKE OF CUTTING MEMBER BASED ON SENSED PARAMETER        OF FIRING OR CLAMPING;    -   U.S. patent application Ser. No. 16/182,235, titled VARIATION OF        RADIO FREQUENCY AND ULTRASONIC POWER LEVEL IN COOPERATION WITH        VARYING CLAMP ARM PRESSURE TO ACHIEVE PREDEFINED HEAT FLUX OR        POWER APPLIED TO TISSUE; and    -   U.S. patent application Ser. No. 16/182,238, titled ULTRASONIC        ENERGY DEVICE WHICH VARIES PRESSURE APPLIED BY CLAMP ARM TO        PROVIDE THRESHOLD CONTROL PRESSURE AT A CUT PROGRESSION        LOCATION.

Applicant of the present application owns the following U.S. patentapplications that were filed on Oct. 26, 2018, the disclosure of each ofwhich is herein incorporated by reference in its entirety:

-   -   U.S. patent application Ser. No. 16/172,303, titled METHOD FOR        OPERATING A POWERED ARTICULATING MULTI-CLIP APPLIER;    -   U.S. patent application Ser. No. 16/172,130, titled CLIP APPLIER        COMPRISING INTERCHANGEABLE CLIP RELOADS;    -   U.S. patent application Ser. No. 16/172,066, titled CLIP APPLIER        COMPRISING A MOVABLE CLIP MAGAZINE;    -   U.S. patent application Ser. No. 16/172,078, titled CLIP APPLIER        COMPRISING A ROTATABLE CLIP MAGAZINE;    -   U.S. patent application Ser. No. 16/172,087, titled CLIP APPLIER        COMPRISING CLIP ADVANCING SYSTEMS;    -   U.S. patent application Ser. No. 16/172,094, titled CLIP APPLIER        COMPRISING A CLIP CRIMPING SYSTEM;    -   U.S. patent application Ser. No. 16/172,128, titled CLIP APPLIER        COMPRISING A RECIPROCATING CLIP ADVANCING MEMBER;    -   U.S. patent application Ser. No. 16/172,168, titled CLIP APPLIER        COMPRISING A MOTOR CONTROLLER;    -   U.S. patent application Ser. No. 16/172,164, titled SURGICAL        SYSTEM COMPRISING A SURGICAL TOOL AND A SURGICAL HUB;    -   U.S. patent application Ser. No. 16/172,328, titled METHOD OF        HUB COMMUNICATION WITH SURGICAL INSTRUMENT SYSTEMS;    -   U.S. patent application Ser. No. 16/172,280, titled METHOD FOR        PRODUCING A SURGICAL INSTRUMENT COMPRISING A SMART ELECTRICAL        SYSTEM;    -   U.S. patent application Ser. No. 16/172,219, titled METHOD OF        HUB COMMUNICATION WITH SURGICAL INSTRUMENT SYSTEMS;    -   U.S. patent application Ser. No. 16/172,248, titled METHOD OF        HUB COMMUNICATION WITH SURGICAL INSTRUMENT SYSTEMS;    -   U.S. patent application Ser. No. 16/172,198, titled METHOD OF        HUB COMMUNICATION WITH SURGICAL INSTRUMENT SYSTEMS; and    -   U.S. patent application Ser. No. 16/172,155, titled METHOD OF        HUB COMMUNICATION WITH SURGICAL INSTRUMENT SYSTEMS.

Applicant of the present application owns the following U.S. patentapplications, filed on Aug. 28, 2018, the disclosure of each of which isherein incorporated by reference in its entirety:

-   -   U.S. patent application Ser. No. 16/115,214, titled ESTIMATING        STATE OF ULTRASONIC END EFFECTOR AND CONTROL SYSTEM THEREFOR;    -   U.S. patent application Ser. No. 16/115,205, titled TEMPERATURE        CONTROL OF ULTRASONIC END EFFECTOR AND CONTROL SYSTEM THEREFOR;    -   U.S. patent application Ser. No. 16/115,233, titled RADIO        FREQUENCY ENERGY DEVICE FOR DELIVERING COMBINED ELECTRICAL        SIGNALS;    -   U.S. patent application Ser. No. 16/115,208, titled CONTROLLING        AN ULTRASONIC SURGICAL INSTRUMENT ACCORDING TO TISSUE LOCATION;    -   U.S. patent application Ser. No. 16/115,220, titled CONTROLLING        ACTIVATION OF AN ULTRASONIC SURGICAL INSTRUMENT ACCORDING TO THE        PRESENCE OF TISSUE;    -   U.S. patent application Ser. No. 16/115,232, titled DETERMINING        TISSUE COMPOSITION VIA AN ULTRASONIC SYSTEM;    -   U.S. patent application Ser. No. 16/115,239, titled DETERMINING        THE STATE OF AN ULTRASONIC ELECTROMECHANICAL SYSTEM ACCORDING TO        FREQUENCY SHIFT;    -   U.S. patent application Ser. No. 16/115,247, titled DETERMINING        THE STATE OF AN ULTRASONIC END EFFECTOR;    -   U.S. patent application Ser. No. 16/115,211, titled SITUATIONAL        AWARENESS OF ELECTROSURGICAL SYSTEMS;    -   U.S. patent application Ser. No. 16/115,226, titled MECHANISMS        FOR CONTROLLING DIFFERENT ELECTROMECHANICAL SYSTEMS OF AN        ELECTROSURGICAL INSTRUMENT;    -   U.S. patent application Ser. No. 16/115,240, titled DETECTION OF        END EFFECTOR EMERSION IN LIQUID;    -   U.S. patent application Ser. No. 16/115,249, titled INTERRUPTION        OF ENERGY DUE TO INADVERTENT CAPACITIVE COUPLING;    -   U.S. patent application Ser. No. 16/115,256, titled INCREASING        RADIO FREQUENCY TO CREATE PADLESS MONOPOLAR LOOP;    -   U.S. patent application Ser. No. 16/115,223, titled BIPOLAR        COMBINATION DEVICE THAT AUTOMATICALLY ADJUSTS PRESSURE BASED ON        ENERGY MODALITY; and    -   U.S. patent application Ser. No. 16/115,238, titled ACTIVATION        OF ENERGY DEVICES.

Applicant of the present application owns the following U.S. patentapplications, filed on Aug. 24, 2018, the disclosure of each of which isherein incorporated by reference in its entirety:

-   -   U.S. patent application Ser. No. 16/112,129, titled SURGICAL        SUTURING INSTRUMENT CONFIGURED TO MANIPULATE TISSUE USING        MECHANICAL AND ELECTRICAL POWER;    -   U.S. patent application Ser. No. 16/112,155, titled SURGICAL        SUTURING INSTRUMENT COMPRISING A CAPTURE WIDTH WHICH IS LARGER        THAN TROCAR DIAMETER;    -   U.S. patent application Ser. No. 16/112,168, titled SURGICAL        SUTURING INSTRUMENT COMPRISING A NON-CIRCULAR NEEDLE;    -   U.S. patent application Ser. No. 16/112,180, titled ELECTRICAL        POWER OUTPUT CONTROL BASED ON MECHANICAL FORCES;    -   U.S. patent application Ser. No. 16/112,193, titled REACTIVE        ALGORITHM FOR SURGICAL SYSTEM;    -   U.S. patent application Ser. No. 16/112,099, titled SURGICAL        INSTRUMENT COMPRISING AN ADAPTIVE ELECTRICAL SYSTEM;    -   U.S. patent application Ser. No. 16/112,112, titled CONTROL        SYSTEM ARRANGEMENTS FOR A MODULAR SURGICAL INSTRUMENT;    -   U.S. patent application Ser. No. 16/112,119, titled ADAPTIVE        CONTROL PROGRAMS FOR A SURGICAL SYSTEM COMPRISING MORE THAN ONE        TYPE OF CARTRIDGE;    -   U.S. patent application Ser. No. 16/112,097, titled SURGICAL        INSTRUMENT SYSTEMS COMPRISING BATTERY ARRANGEMENTS;    -   U.S. patent application Ser. No. 16/112,109, titled SURGICAL        INSTRUMENT SYSTEMS COMPRISING HANDLE ARRANGEMENTS;    -   U.S. patent application Ser. No. 16/112,114, titled SURGICAL        INSTRUMENT SYSTEMS COMPRISING FEEDBACK MECHANISMS;    -   U.S. patent application Ser. No. 16/112,117, titled SURGICAL        INSTRUMENT SYSTEMS COMPRISING LOCKOUT MECHANISMS;    -   U.S. patent application Ser. No. 16/112,095, titled SURGICAL        INSTRUMENTS COMPRISING A LOCKABLE END EFFECTOR SOCKET;    -   U.S. patent application Ser. No. 16/112,121, titled SURGICAL        INSTRUMENTS COMPRISING A SHIFTING MECHANISM;    -   U.S. patent application Ser. No. 16/112,151, titled SURGICAL        INSTRUMENTS COMPRISING A SYSTEM FOR ARTICULATION AND ROTATION        COMPENSATION;    -   U.S. patent application Ser. No. 16/112,154, titled SURGICAL        INSTRUMENTS COMPRISING A BIASED SHIFTING MECHANISM;    -   U.S. patent application Ser. No. 16/112,226, titled SURGICAL        INSTRUMENTS COMPRISING AN ARTICULATION DRIVE THAT PROVIDES FOR        HIGH ARTICULATION ANGLES;    -   U.S. patent application Ser. No. 16/112,062, titled SURGICAL        DISSECTORS AND MANUFACTURING TECHNIQUES;    -   U.S. patent application Ser. No. 16/112,098, titled SURGICAL        DISSECTORS CONFIGURED TO APPLY MECHANICAL AND ELECTRICAL ENERGY;    -   U.S. patent application Ser. No. 16/112,237, titled SURGICAL        CLIP APPLIER CONFIGURED TO STORE CLIPS IN A STORED STATE;    -   U.S. patent application Ser. No. 16/112,245, titled SURGICAL        CLIP APPLIER COMPRISING AN EMPTY CLIP CARTRIDGE LOCKOUT;    -   U.S. patent application Ser. No. 16/112,249, titled SURGICAL        CLIP APPLIER COMPRISING AN AUTOMATIC CLIP FEEDING SYSTEM;    -   U.S. patent application Ser. No. 16/112,253, titled SURGICAL        CLIP APPLIER COMPRISING ADAPTIVE FIRING CONTROL; and    -   U.S. patent application Ser. No. 16/112,257, titled SURGICAL        CLIP APPLIER COMPRISING ADAPTIVE CONTROL IN RESPONSE TO A STRAIN        GAUGE CIRCUIT.

Applicant of the present application owns the following U.S. patentapplications, filed on Jun. 29, 2018, the disclosure of each of which isherein incorporated by reference in its entirety:

-   -   U.S. patent application Ser. No. 16/024,090, titled CAPACITIVE        COUPLED RETURN PATH PAD WITH SEPARABLE ARRAY ELEMENTS;    -   U.S. patent application Ser. No. 16/024,057, titled CONTROLLING        A SURGICAL INSTRUMENT ACCORDING TO SENSED CLOSURE PARAMETERS;    -   U.S. patent application Ser. No. 16/024,067, titled SYSTEMS FOR        ADJUSTING END EFFECTOR PARAMETERS BASED ON PERIOPERATIVE        INFORMATION;    -   U.S. patent application Ser. No. 16/024,075, titled SAFETY        SYSTEMS FOR SMART POWERED SURGICAL STAPLING;    -   U.S. patent application Ser. No. 16/024,083, titled SAFETY        SYSTEMS FOR SMART POWERED SURGICAL STAPLING;    -   U.S. patent application Ser. No. 16/024,094, titled SURGICAL        SYSTEMS FOR DETECTING END EFFECTOR TISSUE DISTRIBUTION        IRREGULARITIES;    -   U.S. patent application Ser. No. 16/024,138, titled SYSTEMS FOR        DETECTING PROXIMITY OF SURGICAL END EFFECTOR TO CANCEROUS        TISSUE;    -   U.S. patent application Ser. No. 16/024,150, titled SURGICAL        INSTRUMENT CARTRIDGE SENSOR ASSEMBLIES;    -   U.S. patent application Ser. No. 16/024,160, titled VARIABLE        OUTPUT CARTRIDGE SENSOR ASSEMBLY;    -   U.S. patent application Ser. No. 16/024,124, titled SURGICAL        INSTRUMENT HAVING A FLEXIBLE ELECTRODE;    -   U.S. patent application Ser. No. 16/024,132, titled SURGICAL        INSTRUMENT HAVING A FLEXIBLE CIRCUIT;    -   U.S. patent application Ser. No. 16/024,141, titled SURGICAL        INSTRUMENT WITH A TISSUE MARKING ASSEMBLY;    -   U.S. patent application Ser. No. 16/024,162, titled SURGICAL        SYSTEMS WITH PRIORITIZED DATA TRANSMISSION CAPABILITIES;    -   U.S. patent application Ser. No. 16/024,066, titled SURGICAL        EVACUATION SENSING AND MOTOR CONTROL;    -   U.S. patent application Ser. No. 16/024,096, titled SURGICAL        EVACUATION SENSOR ARRANGEMENTS;    -   U.S. patent application Ser. No. 16/024,116, titled SURGICAL        EVACUATION FLOW PATHS;    -   U.S. patent application Ser. No. 16/024,149, titled SURGICAL        EVACUATION SENSING AND GENERATOR CONTROL;    -   U.S. patent application Ser. No. 16/024,180, titled SURGICAL        EVACUATION SENSING AND DISPLAY;    -   U.S. patent application Ser. No. 16/024,245, titled        COMMUNICATION OF SMOKE EVACUATION SYSTEM PARAMETERS TO HUB OR        CLOUD IN SMOKE EVACUATION MODULE FOR INTERACTIVE SURGICAL        PLATFORM;    -   U.S. patent application Ser. No. 16/024,258, titled SMOKE        EVACUATION SYSTEM INCLUDING A SEGMENTED CONTROL CIRCUIT FOR        INTERACTIVE SURGICAL PLATFORM;    -   U.S. patent application Ser. No. 16/024,265, titled SURGICAL        EVACUATION SYSTEM WITH A COMMUNICATION CIRCUIT FOR COMMUNICATION        BETWEEN A FILTER AND A SMOKE EVACUATION DEVICE; and    -   U.S. patent application Ser. No. 16/024,273, titled DUAL        IN-SERIES LARGE AND SMALL DROPLET FILTERS.

Applicant of the present application owns the following U.S. patentapplications, filed on Mar. 29, 2018, the disclosure of each of which isherein incorporated by reference in its entirety:

-   -   U.S. patent application Ser. No. 15/940,641, titled INTERACTIVE        SURGICAL SYSTEMS WITH ENCRYPTED COMMUNICATION CAPABILITIES;    -   U.S. patent application Ser. No. 15/940,648, titled INTERACTIVE        SURGICAL SYSTEMS WITH CONDITION HANDLING OF DEVICES AND DATA        CAPABILITIES;    -   U.S. patent application Ser. No. 15/940,656, titled SURGICAL HUB        COORDINATION OF CONTROL AND COMMUNICATION OF OPERATING ROOM        DEVICES;    -   U.S. patent application Ser. No. 15/940,666, titled SPATIAL        AWARENESS OF SURGICAL HUBS IN OPERATING ROOMS;    -   U.S. patent application Ser. No. 15/940,670, titled COOPERATIVE        UTILIZATION OF DATA DERIVED FROM SECONDARY SOURCES BY        INTELLIGENT SURGICAL HUBS;    -   U.S. patent application Ser. No. 15/940,677, titled SURGICAL HUB        CONTROL ARRANGEMENTS;    -   U.S. patent application Ser. No. 15/940,632, titled DATA        STRIPPING METHOD TO INTERROGATE PATIENT RECORDS AND CREATE        ANONYMIZED RECORD;    -   U.S. patent application Ser. No. 15/940,640, titled        COMMUNICATION HUB AND STORAGE DEVICE FOR STORING PARAMETERS AND        STATUS OF A SURGICAL DEVICE TO BE SHARED WITH CLOUD BASED        ANALYTICS SYSTEMS;    -   U.S. patent application Ser. No. 15/940,645, titled SELF        DESCRIBING DATA PACKETS GENERATED AT AN ISSUING INSTRUMENT;    -   U.S. patent application Ser. No. 15/940,649, titled DATA PAIRING        TO INTERCONNECT A DEVICE MEASURED PARAMETER WITH AN OUTCOME;    -   U.S. patent application Ser. No. 15/940,654, titled SURGICAL HUB        SITUATIONAL AWARENESS;    -   U.S. patent application Ser. No. 15/940,663, titled SURGICAL        SYSTEM DISTRIBUTED PROCESSING;    -   U.S. patent application Ser. No. 15/940,668, titled AGGREGATION        AND REPORTING OF SURGICAL HUB DATA;    -   U.S. patent application Ser. No. 15/940,671, titled SURGICAL HUB        SPATIAL AWARENESS TO DETERMINE DEVICES IN OPERATING THEATER;    -   U.S. patent application Ser. No. 15/940,686, titled DISPLAY OF        ALIGNMENT OF STAPLE CARTRIDGE TO PRIOR LINEAR STAPLE LINE;    -   U.S. patent application Ser. No. 15/940,700, titled STERILE        FIELD INTERACTIVE CONTROL DISPLAYS;    -   U.S. patent application Ser. No. 15/940,629, titled COMPUTER        IMPLEMENTED INTERACTIVE SURGICAL SYSTEMS;    -   U.S. patent application Ser. No. 15/940,704, titled USE OF LASER        LIGHT AND RED-GREEN-BLUE COLORATION TO DETERMINE PROPERTIES OF        BACK SCATTERED LIGHT;    -   U.S. patent application Ser. No. 15/940,722, titled        CHARACTERIZATION OF TISSUE IRREGULARITIES THROUGH THE USE OF        MONO-CHROMATIC LIGHT REFRACTIVITY;    -   U.S. patent application Ser. No. 15/940,742, titled DUAL CMOS        ARRAY IMAGING;    -   U.S. patent application Ser. No. 15/940,636, titled ADAPTIVE        CONTROL PROGRAM UPDATES FOR SURGICAL DEVICES;    -   U.S. patent application Ser. No. 15/940,653, titled ADAPTIVE        CONTROL PROGRAM UPDATES FOR SURGICAL HUBS;    -   U.S. patent application Ser. No. 15/940,660, titled CLOUD-BASED        MEDICAL ANALYTICS FOR CUSTOMIZATION AND RECOMMENDATIONS TO A        USER;    -   U.S. patent application Ser. No. 15/940,679, titled CLOUD-BASED        MEDICAL ANALYTICS FOR LINKING OF LOCAL USAGE TRENDS WITH THE        RESOURCE ACQUISITION BEHAVIORS OF LARGER DATA SET;    -   U.S. patent application Ser. No. 15/940,694, titled CLOUD-BASED        MEDICAL ANALYTICS FOR MEDICAL FACILITY SEGMENTED        INDIVIDUALIZATION OF INSTRUMENT FUNCTION;    -   U.S. patent application Ser. No. 15/940,634, titled CLOUD-BASED        MEDICAL ANALYTICS FOR SECURITY AND AUTHENTICATION TRENDS AND        REACTIVE MEASURES;    -   U.S. patent application Ser. No. 15/940,706, titled DATA        HANDLING AND PRIORITIZATION IN A CLOUD ANALYTICS NETWORK;    -   U.S. patent application Ser. No. 15/940,675, titled CLOUD        INTERFACE FOR COUPLED SURGICAL DEVICES;    -   U.S. patent application Ser. No. 15/940,627, titled DRIVE        ARRANGEMENTS FOR ROBOT-ASSISTED SURGICAL PLATFORMS;    -   U.S. patent application Ser. No. 15/940,637, titled        COMMUNICATION ARRANGEMENTS FOR ROBOT-ASSISTED SURGICAL        PLATFORMS;    -   U.S. patent application Ser. No. 15/940,642, titled CONTROLS FOR        ROBOT-ASSISTED SURGICAL PLATFORMS;    -   U.S. patent application Ser. No. 15/940,676, titled AUTOMATIC        TOOL ADJUSTMENTS FOR ROBOT-ASSISTED SURGICAL PLATFORMS;    -   U.S. patent application Ser. No. 15/940,680, titled CONTROLLERS        FOR ROBOT-ASSISTED SURGICAL PLATFORMS;    -   U.S. patent application Ser. No. 15/940,683, titled COOPERATIVE        SURGICAL ACTIONS FOR ROBOT-ASSISTED SURGICAL PLATFORMS;    -   U.S. patent application Ser. No. 15/940,690, titled DISPLAY        ARRANGEMENTS FOR ROBOT-ASSISTED SURGICAL PLATFORMS; and    -   U.S. patent application Ser. No. 15/940,711, titled SENSING        ARRANGEMENTS FOR ROBOT-ASSISTED SURGICAL PLATFORMS.

Applicant of the present application owns the following U.S. ProvisionalPatent Applications, filed on Mar. 8, 2018, the disclosure of each ofwhich is herein incorporated by reference in its entirety:

-   -   U.S. Provisional Patent Application No. 62/640,417, titled        TEMPERATURE CONTROL IN ULTRASONIC DEVICE AND CONTROL SYSTEM        THEREFOR; and    -   U.S. Provisional Patent Application No. 62/640,415, titled        ESTIMATING STATE OF ULTRASONIC END EFFECTOR AND CONTROL SYSTEM        THEREFOR.

Before explaining various aspects of surgical devices and generators indetail, it should be noted that the illustrative examples are notlimited in application or use to the details of construction andarrangement of parts illustrated in the accompanying drawings anddescription. The illustrative examples may be implemented orincorporated in other aspects, variations and modifications, and may bepracticed or carried out in various ways. Further, unless otherwiseindicated, the terms and expressions employed herein have been chosenfor the purpose of describing the illustrative examples for theconvenience of the reader and are not for the purpose of limitationthereof. Also, it will be appreciated that one or more of thefollowing-described aspects, expressions of aspects, and/or examples,can be combined with any one or more of the other following-describedaspects, expressions of aspects and/or examples.

Various aspects are directed to improved ultrasonic surgical devices,electrosurgical devices and generators for use therewith. Aspects of theultrasonic surgical devices can be configured for transecting and/orcoagulating tissue during surgical procedures, for example. Aspects ofthe electrosurgical devices can be configured for transecting,coagulating, scaling, welding and/or desiccating tissue during surgicalprocedures, for example.

Referring to FIG. 1 , a computer-implemented interactive surgical system100 includes one or more surgical systems 102 and a cloud-based system(e.g., the cloud 104 that may include a remote server 113 coupled to astorage device 105). Each surgical system 102 includes at least onesurgical hub 106 in communication with the cloud 104 that may include aremote server 113. In one example, as illustrated in FIG. 1 , thesurgical system 102 includes a visualization system 108, a roboticsystem 110, and a handheld intelligent surgical instrument 112, whichare configured to communicate with one another and/or the hub 106. Insome aspects, a surgical system 102 may include an M number of hubs 106,an N number of visualization systems 108, an O number of robotic systems110, and a P number of handheld intelligent surgical instruments 112,where M, N, O, and P are integers greater than or equal to one.

FIG. 3 depicts an example of a surgical system 102 being used to performa surgical procedure on a patient who is lying down on an operatingtable 114 in a surgical operating room 116. A robotic system 110 is usedin the surgical procedure as a part of the surgical system 102. Therobotic system 110 includes a surgeon's console 118, a patient side cart120 (surgical robot), and a surgical robotic hub 122. The patient sidecart 120 can manipulate at least one removably coupled surgical tool 117through a minimally invasive incision in the body of the patient whilethe surgeon views the surgical site through the surgeon's console 118.An image of the surgical site can be obtained by a medical imagingdevice 124, which can be manipulated by the patient side cart 120 toorient the imaging device 124. The robotic hub 122 can be used toprocess the images of the surgical site for subsequent display to thesurgeon through the surgeon's console 118.

Other types of robotic systems can be readily adapted for use with thesurgical system 102. Various examples of robotic systems and surgicaltools that are suitable for use with the present disclosure aredescribed in U.S. Provisional Patent Application Ser. No. 62/611,339,titled ROBOT ASSISTED SURGICAL PLATFORM, filed Dec. 28, 2017, thedisclosure of which is herein incorporated by reference in its entirety.

Various examples of cloud-based analytics that are performed by thecloud 104, and are suitable for use with the present disclosure, aredescribed in U.S. Provisional Patent Application Ser. No. 62/611,340,titled CLOUD-BASED MEDICAL ANALYTICS, filed Dec. 28, 2017, thedisclosure of which is herein incorporated by reference in its entirety.

In various aspects, the imaging device 124 includes at least one imagesensor and one or more optical components. Suitable image sensorsinclude, but are not limited to, Charge-Coupled Device (CCD) sensors andComplementary Metal-Oxide Semiconductor (CMOS) sensors.

The optical components of the imaging device 124 may include one or moreillumination sources and/or one or more lenses. The one or moreillumination sources may be directed to illuminate portions of thesurgical field. The one or more image sensors may receive lightreflected or refracted from the surgical field, including lightreflected or refracted from tissue and/or surgical instruments.

The one or more illumination sources may be configured to radiateelectromagnetic energy in the visible spectrum as well as the invisiblespectrum. The visible spectrum, sometimes referred to as the opticalspectrum or luminous spectrum, is that portion of the electromagneticspectrum that is visible to (i.e., can be detected by) the human eye andmay be referred to as visible light or simply light. A typical human eyewill respond to wavelengths in air that are from about 380 nm to about750 nm.

The invisible spectrum (i.e., the non-luminous spectrum) is that portionof the electromagnetic spectrum that lies below and above the visiblespectrum (i.e., wavelengths below about 380 nm and above about 750 nm).The invisible spectrum is not detectable by the human eye. Wavelengthsgreater than about 750 nm are longer than the red visible spectrum, andthey become invisible infrared (IR), microwave, and radioelectromagnetic radiation. Wavelengths less than about 380 nm areshorter than the violet spectrum, and they become invisible ultraviolet,x-ray, and gamma ray electromagnetic radiation.

In various aspects, the imaging device 124 is configured for use in aminimally invasive procedure. Examples of imaging devices suitable foruse with the present disclosure include, but not limited to, anarthroscope, angioscope, bronchoscope, choledochoscope, colonoscope,cytoscope, duodenoscope, enteroscope, esophagogastro-duodenoscope(gastroscope), endoscope, laryngoscope, nasopharyngo-neproscope,sigmoidoscope, thoracoscope, and ureteroscope.

In one aspect, the imaging device employs multi-spectrum monitoring todiscriminate topography and underlying structures. A multi-spectralimage is one that captures image data within specific wavelength rangesacross the electromagnetic spectrum. The wavelengths may be separated byfilters or by the use of instruments that are sensitive to particularwavelengths, including light from frequencies beyond the visible lightrange, e.g., IR and ultraviolet. Spectral imaging can allow extractionof additional information the human eye fails to capture with itsreceptors for red, green, and blue. The use of multi-spectral imaging isdescribed in greater detail under the heading “Advanced ImagingAcquisition Module” in U.S. Provisional Patent Application Ser. No.62/611,341, titled INTERACTIVE SURGICAL PLATFORM, filed Dec. 28, 2017,the disclosure of which is herein incorporated by reference in itsentirety. Multi-spectrum monitoring can be a useful tool in relocating asurgical field after a surgical task is completed to perform one or moreof the previously described tests on the treated tissue.

It is axiomatic that strict sterilization of the operating room andsurgical equipment is required during any surgery. The strict hygieneand sterilization conditions required in a “surgical theater,” i.e., anoperating or treatment room, necessitate the highest possible sterilityof all medical devices and equipment. Part of that sterilization processis the need to sterilize anything that comes in contact with the patientor penetrates the sterile field, including the imaging device 124 andits attachments and components. It will be appreciated that the sterilefield may be considered a specified area, such as within a tray or on asterile towel, that is considered free of microorganisms, or the sterilefield may be considered an area, immediately around a patient, who hasbeen prepared for a surgical procedure. The sterile field may includethe scrubbed team members, who are properly attired, and all furnitureand fixtures in the area.

In various aspects, the visualization system 108 includes one or moreimaging sensors, one or more image-processing units, one or more storagearrays, and one or more displays that are strategically arranged withrespect to the sterile field, as illustrated in FIG. 2 . In one aspect,the visualization system 108 includes an interface for HL7, PACS, andEMR. Various components of the visualization system 108 are describedunder the heading “Advanced Imaging Acquisition Module” in U.S.Provisional Patent Application Ser. No. 62/611,341, titled INTERACTIVESURGICAL PLATFORM, filed Dec. 28, 2017, the disclosure of which isherein incorporated by reference in its entirety.

As illustrated in FIG. 2 , a primary display 119 is positioned in thesterile field to be visible to an operator at the operating table 114.In addition, a visualization tower 111 is positioned outside the sterilefield. The visualization tower 111 includes a first non-sterile display107 and a second non-sterile display 109, which face away from eachother. The visualization system 108, guided by the hub 106, isconfigured to utilize the displays 107, 109, and 119 to coordinateinformation flow to operators inside and outside the sterile field. Forexample, the hub 106 may cause the visualization system 108 to display asnapshot of a surgical site, as recorded by an imaging device 124, on anon-sterile display 107 or 109, while maintaining a live feed of thesurgical site on the primary display 119. The snapshot on thenon-sterile display 107 or 109 can permit a non-sterile operator toperform a diagnostic step relevant to the surgical procedure, forexample.

In one aspect, the hub 106 is also configured to route a diagnosticinput or feedback entered by a non-sterile operator at the visualizationtower 111 to the primary display 119 within the sterile field, where itcan be viewed by a sterile operator at the operating table. In oneexample, the input can be in the form of a modification to the snapshotdisplayed on the non-sterile display 107 or 109, which can be routed tothe primary display 119 by the hub 106.

Referring to FIG. 2 , a surgical instrument 112 is being used in thesurgical procedure as part of the surgical system 102. The hub 106 isalso configured to coordinate information flow to a display of thesurgical instrument 112. For example, in U.S. Provisional PatentApplication Ser. No. 62/611,341, titled INTERACTIVE SURGICAL PLATFORM,filed Dec. 28, 2017, the disclosure of which is herein incorporated byreference in its entirety. A diagnostic input or feedback entered by anon-sterile operator at the visualization tower 111 can be routed by thehub 106 to the surgical instrument display 115 within the sterile field,where it can be viewed by the operator of the surgical instrument 112.Example surgical instruments that are suitable for use with the surgicalsystem 102 are described under the heading “Surgical InstrumentHardware” and in U.S. Provisional Patent Application Ser. No.62/611,341, titled INTERACTIVE SURGICAL PLATFORM, filed Dec. 28, 2017,the disclosure of which is herein incorporated by reference in itsentirety, for example.

Referring now to FIG. 3 , a hub 106 is depicted in communication with avisualization system 108, a robotic system 110, and a handheldintelligent surgical instrument 112. The hub 106 includes a hub display135, an imaging module 138, a generator module 140, a communicationmodule 130, a processor module 132, and a storage array 134. In certainaspects, as illustrated in FIG. 3 , the hub 106 further includes a smokeevacuation module 126 and/or a suction/irrigation module 128.

During a surgical procedure, energy application to tissue, for sealingand/or cutting, is generally associated with smoke evacuation, suctionof excess fluid, and/or irrigation of the tissue. Fluid, power, and/ordata lines from different sources are often entangled during thesurgical procedure. Valuable time can be lost addressing this issueduring a surgical procedure. Detangling the lines may necessitatedisconnecting the lines from their respective modules, which may requireresetting the modules. The hub modular enclosure 136 offers a unifiedenvironment for managing the power, data, and fluid lines, which reducesthe frequency of entanglement between such lines.

Aspects of the present disclosure present a surgical hub for use in asurgical procedure that involves energy application to tissue at asurgical site. The surgical hub includes a hub enclosure and a combogenerator module slidably receivable in a docking station of the hubenclosure. The docking station includes data and power contacts. Thecombo generator module includes two or more of an ultrasonic energygenerator component, a bipolar RF energy generator component, and amonopolar RF energy generator component that are housed in a singleunit. In one aspect, the combo generator module also includes a smokeevacuation component, at least one energy delivery cable for connectingthe combo generator module to a surgical instrument, at least one smokeevacuation component configured to evacuate smoke, fluid, and/orparticulates generated by the application of therapeutic energy to thetissue, and a fluid line extending from the remote surgical site to thesmoke evacuation component.

In one aspect, the fluid line is a first fluid line and a second fluidline extends from the remote surgical site to a suction and irrigationmodule slidably received in the hub enclosure. In one aspect, the hubenclosure comprises a fluid interface.

Certain surgical procedures may require the application of more than oneenergy type to the tissue. One energy type may be more beneficial forcutting the tissue, while another different energy type may be morebeneficial for sealing the tissue. For example, a bipolar generator canbe used to seal the tissue while an ultrasonic generator can be used tocut the sealed tissue. Aspects of the present disclosure present asolution where a hub modular enclosure 136 is configured to accommodatedifferent generators, and facilitate an interactive communicationtherebetween. One of the advantages of the hub modular enclosure 136 isenabling the quick removal and/or replacement of various modules.

Aspects of the present disclosure present a modular surgical enclosurefor use in a surgical procedure that involves energy application totissue. The modular surgical enclosure includes a first energy-generatormodule, configured to generate a first energy for application to thetissue, and a first docking station comprising a first docking port thatincludes first data and power contacts, wherein the firstenergy-generator module is slidably movable into an electricalengagement with the power and data contacts and wherein the firstenergy-generator module is slidably movable out of the electricalengagement with the first power and data contacts,

Further to the above, the modular surgical enclosure also includes asecond energy-generator module configured to generate a second energy,different than the first energy, for application to the tissue, and asecond docking station comprising a second docking port that includessecond data and power contacts, wherein the second energy-generatormodule is slidably movable into an electrical engagement with the powerand data contacts, and wherein the second energy-generator module isslidably movable out of the electrical engagement with the second powerand data contacts.

In addition, the modular surgical enclosure also includes acommunication bus between the first docking port and the second dockingport, configured to facilitate communication between the firstenergy-generator module and the second energy-generator module.

Referring to FIGS. 3-7 , aspects of the present disclosure are presentedfor a hub modular enclosure 136 that allows the modular integration of agenerator module 140, a smoke evacuation module 126, and asuction/irrigation module 128. The hub modular enclosure 136 furtherfacilitates interactive communication between the modules 140, 126, 128.As illustrated in FIG. 5 , the generator module 140 can be a generatormodule with integrated monopolar, bipolar, and ultrasonic componentssupported in a single housing unit 139 slidably insertable into the hubmodular enclosure 136. As illustrated in FIG. 5 , the generator module140 can be configured to connect to a monopolar device 146, a bipolardevice 147, and an ultrasonic device 148. Alternatively, the generatormodule 140 may comprise a series of monopolar, bipolar, and/orultrasonic generator modules that interact through the hub modularenclosure 136. The hub modular enclosure 136 can be configured tofacilitate the insertion of multiple generators and interactivecommunication between the generators docked into the hub modularenclosure 136 so that the generators would act as a single generator.

In one aspect, the hub modular enclosure 136 comprises a modular powerand communication backplane 149 with external and wireless communicationheaders to enable the removable attachment of the modules 140, 126, 128and interactive communication therebetween.

In one aspect, the hub modular enclosure 136 includes docking stations,or drawers, 151, herein also referred to as drawers, which areconfigured to slidably receive the modules 140, 126, 128. FIG. 4illustrates a partial perspective view of a surgical hub enclosure 136,and a combo generator module 145 slidably receivable in a dockingstation 151 of the surgical hub enclosure 136. A docking port 152 withpower and data contacts on a rear side of the combo generator module 145is configured to engage a corresponding docking port 150 with power anddata contacts of a corresponding docking station 151 of the hub modularenclosure 136 as the combo generator module 145 is slid into positionwithin the corresponding docking station 151 of the hub module enclosure136. In one aspect, the combo generator module 145 includes a bipolar,ultrasonic, and monopolar module and a smoke evacuation moduleintegrated together into a single housing unit 139, as illustrated inFIG. 5 .

In various aspects, the smoke evacuation module 126 includes a fluidline 154 that conveys captured/collected smoke and/or fluid away from asurgical site and to, for example, the smoke evacuation module 126.Vacuum suction originating from the smoke evacuation module 126 can drawthe smoke into an opening of a utility conduit at the surgical site. Theutility conduit, coupled to the fluid line, can be in the form of aflexible tube terminating at the smoke evacuation module 126. Theutility conduit and the fluid line define a fluid path extending towardthe smoke evacuation module 126 that is received in the hub enclosure136.

In various aspects, the suction/irrigation module 128 is coupled to asurgical tool comprising an aspiration fluid line and a suction fluidline. In one example, the aspiration and suction fluid lines are in theform of flexible tubes extending from the surgical site toward thesuction/irrigation module 128. One or more drive systems can beconfigured to cause irrigation and aspiration of fluids to and from thesurgical site.

In one aspect, the surgical tool includes a shaft having an end effectorat a distal end thereof and at least one energy treatment associatedwith the end effector, an aspiration tube, and an irrigation tube. Theaspiration tube can have an inlet port at a distal end thereof and theaspiration tube extends through the shaft. Similarly, an irrigation tubecan extend through the shaft and can have an inlet port in proximity tothe energy deliver implement. The energy deliver implement is configuredto deliver ultrasonic and/or RF energy to the surgical site and iscoupled to the generator module 140 by a cable extending initiallythrough the shaft.

The irrigation tube can be in fluid communication with a fluid source,and the aspiration tube can be in fluid communication with a vacuumsource. The fluid source and/or the vacuum source can be housed in thesuction/irrigation module 128. In one example, the fluid source and/orthe vacuum source can be housed in the hub enclosure 136 separately fromthe suction/irrigation module 128. In such example, a fluid interfacecan be configured to connect the suction/irrigation module 128 to thefluid source and/or the vacuum source.

In one aspect, the modules 140, 126, 128 and/or their correspondingdocking stations on the hub modular enclosure 136 may include alignmentfeatures that are configured to align the docking ports of the modulesinto engagement with their counterparts in the docking stations of thehub modular enclosure 136. For example, as illustrated in FIG. 4 , thecombo generator module 145 includes side brackets 155 that areconfigured to slidably engage with corresponding brackets 156 of thecorresponding docking station 151 of the hub modular enclosure 136. Thebrackets cooperate to guide the docking port contacts of the combogenerator module 145 into an electrical engagement with the docking portcontacts of the hub modular enclosure 136.

In some aspects, the drawers 151 of the hub modular enclosure 136 arethe same, or substantially the same size, and the modules are adjustedin size to be received in the drawers 151. For example, the sidebrackets 155 and/or 156 can be larger or smaller depending on the sizeof the module. In other aspects, the drawers 151 are different in sizeand are each designed to accommodate a particular module.

Furthermore, the contacts of a particular module can be keyed forengagement with the contacts of a particular drawer to avoid inserting amodule into a drawer with mismatching contacts.

As illustrated in FIG. 4 , the docking port 150 of one drawer 151 can becoupled to the docking port 150 of another drawer 151 through acommunications link 157 to facilitate an interactive communicationbetween the modules housed in the hub modular enclosure 136. The dockingports 150 of the hub modular enclosure 136 may alternatively, oradditionally, facilitate a wireless interactive communication betweenthe modules housed in the hub modular enclosure 136. Any suitablewireless communication can be employed, such as for example AirTitan-Bluetooth.

FIG. 6 illustrates individual power bus attachments for a plurality oflateral docking ports of a lateral modular housing 160 configured toreceive a plurality of modules of a surgical hub 206. The lateralmodular housing 160 is configured to laterally receive and interconnectthe modules 161. The modules 161 are slidably inserted into dockingstations 162 of lateral modular housing 160, which includes a backplanefor interconnecting the modules 161. As illustrated in FIG. 6 , themodules 161 are arranged laterally in the lateral modular housing 160.Alternatively, the modules 161 may be arranged vertically in a lateralmodular housing.

FIG. 7 illustrates a vertical modular housing 164 configured to receivea plurality of modules 165 of the surgical hub 106. The modules 165 areslidably inserted into docking stations, or drawers, 167 of verticalmodular housing 164, which includes a backplane for interconnecting themodules 165. Although the drawers 167 of the vertical modular housing164 are arranged vertically, in certain instances, a vertical modularhousing 164 may include drawers that are arranged laterally.Furthermore, the modules 165 may interact with one another through thedocking ports of the vertical modular housing 164. In the example ofFIG. 7 , a display 177 is provided for displaying data relevant to theoperation of the modules 165. In addition, the vertical modular housing164 includes a master module 178 housing a plurality of sub-modules thatare slidably received in the master module 178.

In various aspects, the imaging module 138 comprises an integrated videoprocessor and a modular light source and is adapted for use with variousimaging devices. In one aspect, the imaging device is comprised of amodular housing that can be assembled with a light source module and acamera module. The housing can be a disposable housing. In at least oneexample, the disposable housing is removably coupled to a reusablecontroller, a light source module, and a camera module. The light sourcemodule and/or the camera module can be selectively chosen depending onthe type of surgical procedure. In one aspect, the camera modulecomprises a CCD sensor. In another aspect, the camera module comprises aCMOS sensor. In another aspect, the camera module is configured forscanned beam imaging. Likewise, the light source module can beconfigured to deliver a white light or a different light, depending onthe surgical procedure.

During a surgical procedure, removing a surgical device from thesurgical field and replacing it with another surgical device thatincludes a different camera or a different light source can beinefficient. Temporarily losing sight of the surgical field may lead toundesirable consequences. The module imaging device of the presentdisclosure is configured to permit the replacement of a light sourcemodule or a camera module midstream during a surgical procedure, withouthaving to remove the imaging device from the surgical field.

In one aspect, the imaging device comprises a tubular housing thatincludes a plurality of channels. A first channel is configured toslidably receive the camera module, which can be configured for asnap-fit engagement with the first channel. A second channel isconfigured to slidably receive the light source module, which can beconfigured for a snap-fit engagement with the second channel. In anotherexample, the camera module and/or the light source module can be rotatedinto a final position within their respective channels. A threadedengagement can be employed in lieu of the snap-fit engagement.

In various examples, multiple imaging devices are placed at differentpositions in the surgical field to provide multiple views. The imagingmodule 138 can be configured to switch between the imaging devices toprovide an optimal view. In various aspects, the imaging module 138 canbe configured to integrate the images from the different imaging device.

Various image processors and imaging devices suitable for use with thepresent disclosure are described in U.S. Pat. No. 7,995,045, titledCOMBINED SBI AND CONVENTIONAL IMAGE PROCESSOR, which issued on Aug. 9,2011, which is herein incorporated by reference in its entirety. Inaddition, U.S. Pat. No. 7,982,776, titled SBI MOTION ARTIFACT REMOVALAPPARATUS AND METHOD, which issued on Jul. 19, 2011, which is hereinincorporated by reference in its entirety, describes various systems forremoving motion artifacts from image data. Such systems can beintegrated with the imaging module 138. Furthermore, U.S. PatentApplication Publication No. 2011/0306840, titled CONTROLLABLE MAGNETICSOURCE TO FIXTURE INTRACORPOREAL APPARATUS, which published on Dec. 15,2011, and U.S. Patent Application Publication No. 2014/0243597, titledSYSTEM FOR PERFORMING A MINIMALLY INVASIVE SURGICAL PROCEDURE, whichpublished on Aug. 28, 2014, each of which is herein incorporated byreference in its entirety.

FIG. 8 illustrates a surgical data network 201 comprising a modularcommunication hub 203 configured to connect modular devices located inone or more operating theaters of a healthcare facility, or any room ina healthcare facility specially equipped for surgical operations, to acloud-based system (e.g., the cloud 204 that may include a remote server213 coupled to a storage device 205). In one aspect, the modularcommunication hub 203 comprises a network hub 207 and/or a networkswitch 209 in communication with a network router. The modularcommunication hub 203 also can be coupled to a local computer system 210to provide local computer processing and data manipulation. The surgicaldata network 201 may be configured as passive, intelligent, orswitching. A passive surgical data network serves as a conduit for thedata, enabling it to go from one device (or segment) to another and tothe cloud computing resources. An intelligent surgical data networkincludes additional features to enable the traffic passing through thesurgical data network to be monitored and to configure each port in thenetwork hub 207 or network switch 209. An intelligent surgical datanetwork may be referred to as a manageable hub or switch. A switchinghub reads the destination address of each packet and then forwards thepacket to the correct port.

Modular devices 1 a-1 n located in the operating theater may be coupledto the modular communication hub 203. The network hub 207 and/or thenetwork switch 209 may be coupled to a network router 211 to connect thedevices 1 a-1 n to the cloud 204 or the local computer system 210. Dataassociated with the devices 1 a-1 n may be transferred to cloud-basedcomputers via the router for remote data processing and manipulation.Data associated with the devices 1 a-1 n may also be transferred to thelocal computer system 210 for local data processing and manipulation.Modular devices 2 a-2 m located in the same operating theater also maybe coupled to a network switch 209. The network switch 209 may becoupled to the network hub 207 and/or the network router 211 to connectto the devices 2 a-2 m to the cloud 204. Data associated with thedevices 2 a-2 n may be transferred to the cloud 204 via the networkrouter 211 for data processing and manipulation. Data associated withthe devices 2 a-2 m may also be transferred to the local computer system210 for local data processing and manipulation.

It will be appreciated that the surgical data network 201 may beexpanded by interconnecting multiple network hubs 207 and/or multiplenetwork switches 209 with multiple network routers 211. The modularcommunication hub 203 may be contained in a modular control towerconfigured to receive multiple devices 1 a-1 n/2 a-2 m. The localcomputer system 210 also may be contained in a modular control tower.The modular communication hub 203 is connected to a display 212 todisplay images obtained by some of the devices 1 a-1 n/2 a-2 m, forexample during surgical procedures. In various aspects, the devices 1a-1 n/2 a-2 m may include, for example, various modules such as animaging module 138 coupled to an endoscope, a generator module 140coupled to an energy-based surgical device, a smoke evacuation module126, a suction/irrigation module 128, a communication module 130, aprocessor module 132, a storage array 134, a surgical device coupled toa display, and/or a non-contact sensor module, among other modulardevices that may be connected to the modular communication hub 203 ofthe surgical data network 201.

In one aspect, the surgical data network 201 may comprise a combinationof network hub(s), network switch(es), and network router(s) connectingthe devices 1 a-1 n/2 a-2 m to the cloud. Any one of or all of thedevices 1 a-1 n/2 a-2 m coupled to the network hub or network switch maycollect data in real time and transfer the data to cloud computers fordata processing and manipulation. It will be appreciated that cloudcomputing relies on sharing computing resources rather than having localservers or personal devices to handle software applications. The word“cloud” may be used as a metaphor for “the Internet,” although the termis not limited as such. Accordingly, the term “cloud computing” may beused herein to refer to “a type of Internet-based computing,” wheredifferent services-such as servers, storage, and applications—aredelivered to the modular communication hub 203 and/or computer system210 located in the surgical theater (e.g., a fixed, mobile, temporary,or field operating room or space) and to devices connected to themodular communication hub 203 and/or computer system 210 through theInternet. The cloud infrastructure may be maintained by a cloud serviceprovider. In this context, the cloud service provider may be the entitythat coordinates the usage and control of the devices 1 a-1 n/2 a-2 mlocated in one or more operating theaters. The cloud computing servicescan perform a large number of calculations based on the data gathered bysmart surgical instruments, robots, and other computerized deviceslocated in the operating theater. The hub hardware enables multipledevices or connections to be connected to a computer that communicateswith the cloud computing resources and storage.

Applying cloud computer data processing techniques on the data collectedby the devices 1 a-1 n/2 a-2 m, the surgical data network providesimproved surgical outcomes, reduced costs, and improved patientsatisfaction. At least some of the devices 1 a-1 n/2 a-2 m may beemployed to view tissue states to assess leaks or perfusion of sealedtissue after a tissue sealing and cutting procedure. At least some ofthe devices 1 a-1 n/2 a-2 m may be employed to identify pathology, suchas the effects of diseases, using the cloud-based computing to examinedata including images of samples of body tissue for diagnostic purposes.This includes localization and margin confirmation of tissue andphenotypes. At least some of the devices 1 a-1 n/2 a-2 m may be employedto identify anatomical structures of the body using a variety of sensorsintegrated with imaging devices and techniques such as overlaying imagescaptured by multiple imaging devices. The data gathered by the devices 1a-1 n/2 a-2 m, including image data, may be transferred to the cloud 204or the local computer system 210 or both for data processing andmanipulation including image processing and manipulation. The data maybe analyzed to improve surgical procedure outcomes by determining iffurther treatment, such as the application of endoscopic intervention,emerging technologies, a targeted radiation, targeted intervention, andprecise robotics to tissue-specific sites and conditions, may bepursued. Such data analysis may further employ outcome analyticsprocessing, and using standardized approaches may provide beneficialfeedback to either confirm surgical treatments and the behavior of thesurgeon or suggest modifications to surgical treatments and the behaviorof the surgeon.

In one implementation, the operating theater devices 1 a-1 n may beconnected to the modular communication hub 203 over a wired channel or awireless channel depending on the configuration of the devices 1 a-1 nto a network hub. The network hub 207 may be implemented, in one aspect,as a local network broadcast device that works on the physical layer ofthe Open System Interconnection (OSI) model. The network hub providesconnectivity to the devices 1 a-1 n located in the same operatingtheater network. The network hub 207 collects data in the form ofpackets and sends them to the router in half duplex mode. The networkhub 207 does not store any media access control/Internet Protocol(MAC/IP) to transfer the device data. Only one of the devices 1 a-1 ncan send data at a time through the network hub 207. The network hub 207has no outing tables or intelligence regarding where to send informationand broadcasts all network data across each connection and to a remoteserver 213 (FIG. 9 ) over the cloud 204. The network hub 207 can detectbasic network errors such as collisions, but having all informationbroadcast to multiple ports can be a security risk and causebottlenecks.

In another implementation, the operating theater devices 2 a-2 m may beconnected to a network switch 209 over a wired channel or a wirelesschannel. The network switch 209 works in the data link layer of the OSImodel. The network switch 209 is a multicast device for connecting thedevices 2 a-2 m located in the same operating theater to the network.The network switch 209 sends data in the form of frames to the networkrouter 211 and works in full duplex mode. Multiple devices 2 a-2 m cansend data at the same time through the network switch 209. The networkswitch 209 stores and uses MAC addresses of the devices 2 a-2 m totransfer data.

The network hub 207 and/or the network switch 209 are coupled to thenetwork router 211 for connection to the cloud 204. The network router211 works in the network layer of the OSI model. The network router 211creates a route for transmitting data packets received from the networkhub 207 and/or network switch 211 to cloud-based computer resources forfurther processing and manipulation of the data collected by any one ofor all the devices 1 a-1 n/2 a-2 m. The network router 211 may beemployed to connect two or more different networks located in differentlocations, such as, for example, different operating theaters of thesame healthcare facility or different networks located in differentoperating theaters of different healthcare facilities. The networkrouter 211 sends data in the form of packets to the cloud 204 and worksin full duplex mode. Multiple devices can send data at the same time.The network router 211 uses IP addresses to transfer data.

In one example, the network hub 207 may be implemented as a USB hub,which allows multiple USB devices to be connected to a host computer.The USB hub may expand a single USB port into several tiers so thatthere are more ports available to connect devices to the host systemcomputer. The network hub 207 may include wired or wireless capabilitiesto receive information over a wired channel or a wireless channel. Inone aspect, a wireless USB short-range, high-bandwidth wireless radiocommunication protocol may be employed for communication between thedevices 1 a-1 n and devices 2 a-2 m located in the operating theater.

In other examples, the operating theater devices 1 a-1 n/2 a-2 m maycommunicate to the modular communication hub 203 via Bluetooth wirelesstechnology standard for exchanging data over short distances (usingshort-wavelength UHF radio waves in the ISM band from 2.4 to 2.485 GHz)from fixed and mobile devices and building personal area networks(PANs). In other aspects, the operating theater devices 1 a-1 n/2 a-2 mmay communicate to the modular communication hub 203 via a number ofwireless or wired communication standards or protocols, including butnot limited to Wi-Fi (IEEE 802.11 family), WiMAX (IEEE 802.16 family),IEEE 802.20, long-term evolution (LTE), and Ev-DO, HSPA+, HSDPA+,HSUPA+, EDGE, GSM, GPRS, CDMA, TDMA, DECT, and Ethernet derivativesthereof, as well as any other wireless and wired protocols that aredesignated as 3G, 4G, 5G, and beyond. The computing module may include aplurality of communication modules. For instance, a first communicationmodule may be dedicated to shorter-range wireless communications such asWi-Fi and Bluetooth, and a second communication module may be dedicatedto longer-range wireless communications such as GPS, EDGE, GPRS, CDMA,WiMAX, LTE, Ev-DO, and others.

The modular communication hub 203 may serve as a central connection forone or all of the operating theater devices 1 a-1 n/2 a-2 m and handlesa data type known as frames. Frames carry the data generated by thedevices 1 a-1 n/2 a-2 m. When a frame is received by the modularcommunication hub 203, it is amplified and transmitted to the networkrouter 211, which transfers the data to the cloud computing resources byusing a number of wireless or wired communication standards orprotocols, as described herein.

The modular communication hub 203 can be used as a standalone device orbe connected to compatible network hubs and network switches to form alarger network. The modular communication hub 203 is generally easy toinstall, configure, and maintain, making it a good option for networkingthe operating theater devices 1 a-1 n/2 a-2 m.

FIG. 9 illustrates a computer-implemented interactive surgical system200. The computer-implemented interactive surgical system 200 is similarin many respects to the computer-implemented interactive surgical system100. For example, the computer-implemented interactive surgical system200 includes one or more surgical systems 202, which are similar in manyrespects to the surgical systems 102. Each surgical system 202 includesat least one surgical hub 206 in communication with a cloud 204 that mayinclude a remote server 213. In one aspect, the computer-implementedinteractive surgical system 200 comprises a modular control tower 236connected to multiple operating theater devices such as, for example,intelligent surgical instruments, robots, and other computerized deviceslocated in the operating theater. As shown in FIG. 10 , the modularcontrol tower 236 comprises a modular communication hub 203 coupled to acomputer system 210. As illustrated in the example of FIG. 9 , themodular control tower 236 is coupled to an imaging module 238 that iscoupled to an endoscope 239, a generator module 240 that is coupled toan energy device 241, a smoke evacuator module 226, a suction/irrigationmodule 228, a communication module 230, a processor module 232, astorage array 234, a smart device/instrument 235 optionally coupled to adisplay 237, and a non-contact sensor module 242. The operating theaterdevices are coupled to cloud computing resources and data storage viathe modular control tower 236. A robot hub 222 also may be connected tothe modular control tower 236 and to the cloud computing resources. Thedevices/instruments 235, visualization systems 208, among others, may becoupled to the modular control tower 236 via wired or wirelesscommunication standards or protocols, as described herein. The modularcontrol tower 236 may be coupled to a hub display 215 (e.g., monitor,screen) to display and overlay images received from the imaging module,device/instrument display, and/or other visualization systems 208. Thehub display also may display data received from devices connected to themodular control tower in conjunction with images and overlaid images.

FIG. 10 illustrates a surgical hub 206 comprising a plurality of modulescoupled to the modular control tower 236. The modular control tower 236comprises a modular communication hub 203, e.g., a network connectivitydevice, and a computer system 210 to provide local processing,visualization, and imaging, for example. As shown in FIG. 10 , themodular communication hub 203 may be connected in a tiered configurationto expand the number of modules (e.g., devices) that may be connected tothe modular communication hub 203 and transfer data associated with themodules to the computer system 210, cloud computing resources, or both.As shown in FIG. 10 , each of the network hubs/switches in the modularcommunication hub 203 includes three downstream ports and one upstreamport. The upstream network hub/switch is connected to a processor toprovide a communication connection to the cloud computing resources anda local display 217. Communication to the cloud 204 may be made eitherthrough a wired or a wireless communication channel.

The surgical hub 206 employs a non-contact sensor module 242 to measurethe dimensions of the operating theater and generate a map of thesurgical theater using either ultrasonic or laser-type non-contactmeasurement devices. An ultrasound-based non-contact sensor module scansthe operating theater by transmitting a burst of ultrasound andreceiving the echo when it bounces off the perimeter walls of anoperating theater as described under the heading “Surgical Hub SpatialAwareness Within an Operating Room” in U.S. Provisional PatentApplication Ser. No. 62/611,341, titled INTERACTIVE SURGICAL PLATFORM,filed Dec. 28, 2017, which is herein incorporated by reference in itsentirety, in which the sensor module is configured to determine the sizeof the operating theater and to adjust Bluetooth-pairing distancelimits. A laser-based non-contact sensor module scans the operatingtheater by transmitting laser light pulses, receiving laser light pulsesthat bounce off the perimeter walls of the operating theater, andcomparing the phase of the transmitted pulse to the received pulse todetermine the size of the operating theater and to adjust Bluetoothpairing distance limits, for example.

The computer system 210 comprises a processor 244 and a networkinterface 245. The processor 244 is coupled to a communication module247, storage 248, memory 249, non-volatile memory 250, and input/outputinterface 251 via a system bus. The system bus can be any of severaltypes of bus structure(s) including the memory bus or memory controller,a peripheral bus or external bus, and/or a local bus using any varietyof available bus architectures including, but not limited to, 9-bit bus,Industrial Standard Architecture (ISA), Micro-Charmel Architecture(MSA), Extended ISA (EISA), Intelligent Drive Electronics (IDE), VESALocal Bus (VLB), Peripheral Component Interconnect (PCI), USB, AdvancedGraphics Port (AGP), Personal Computer Memory Card InternationalAssociation bus (PCMCIA), Small Computer Systems Interface (SCSI), orany other proprietary bus.

The processor 244 may be any single-core or multicore processor such asthose known under the trade name ARM Cortex by Texas Instruments. In oneaspect, the processor may be an LM4F230H5QR ARM Cortex-M4F ProcessorCore, available from Texas Instruments, for example, comprising anon-chip memory of 256 KB single-cycle flash memory, or othernon-volatile memory, up to 40 MHz, a prefetch buffer to improveperformance above 40 MHz, a 32 KB single-cycle serial random accessmemory (SRAM), an internal read-only memory (ROM) loaded withStellarisWare® software, a 2 KB electrically erasable programmableread-only memory (EEPROM), and/or one or more pulse width modulation(PWM) modules, one or more quadrature encoder inputs (QEI) analogs, oneor more 12-bit analog-to-digital converters (ADCs) with 12 analog inputchannels, details of which are available for the product datasheet.

In one aspect, the processor 244 may comprise a safety controllercomprising two controller-based families such as TMS570 and RM4x, knownunder the trade name Hercules ARM Cortex R4, also by Texas Instruments.The safety controller may be configured specifically for IEC 61508 andISO 26262 safety critical applications, among others, to provideadvanced integrated safety features while delivering scalableperformance, connectivity, and memory options.

The system memory includes volatile memory and non-volatile memory. Thebasic input/output system (BIOS), containing the basic routines totransfer information between elements within the computer system, suchas during start-up, is stored in non-volatile memory. For example, thenon-volatile memory can include ROM, programmable ROM (PROM),electrically programmable ROM (EPROM), EEPROM, or flash memory. Volatilememory includes random-access memory (RAM), which acts as external cachememory. Moreover, RAM is available in many forms such as SRAM, dynamicRAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), Synchlink DRAM (SLDRAM), and directRambus RAM (DRRAM).

The computer system 210 also includes removable/non-removable,volatile/non-volatile computer storage media, such as for example diskstorage. The disk storage includes, but is not limited to, devices likea magnetic disk drive, floppy disk drive, tape drive, Jaz drive, Zipdrive, LS-60 drive, flash memory card, or memory stick. In addition, thedisk storage can include storage media separately or in combination withother storage media including, but not limited to, an optical disc drivesuch as a compact disc ROM device (CD-ROM), compact disc recordabledrive (CD-R Drive), compact disc rewritable drive (CD-RW Drive), or adigital versatile disc ROM drive (DVD-ROM). To facilitate the connectionof the disk storage devices to the system bus, a removable ornon-removable interface may be employed.

It is to be appreciated that the computer system 210 includes softwarethat acts as an intermediary between users and the basic computerresources described in a suitable operating environment. Such softwareincludes an operating system. The operating system, which can be storedon the disk storage, acts to control and allocate resources of thecomputer system. System applications take advantage of the management ofresources by the operating system through program modules and programdata stored either in the system memory or on the disk storage. It is tobe appreciated that various components described herein can beimplemented with various operating systems or combinations of operatingsystems.

A user enters commands or information into the computer system 210through input device(s) coupled to the I/O interface 251. The inputdevices include, but are not limited to, a pointing device such as amouse, trackball, stylus, touch pad, keyboard, microphone, joystick,game pad, satellite dish, scanner, TV tuner card, digital camera,digital video camera, web camera, and the like. These and other inputdevices connect to the processor through the system bus via interfaceport(s). The interface port(s) include, for example, a serial port, aparallel port, a game port, and a USB. The output device(s) use some ofthe same types of ports as input device(s). Thus, for example, a USBport may be used to provide input to the computer system and to outputinformation from the computer system to an output device. An outputadapter is provided to illustrate that there are some output deviceslike monitors, displays, speakers, and printers, among other outputdevices that require special adapters. The output adapters include, byway of illustration and not limitation, video and sound cards thatprovide a means of connection between the output device and the systembus. It should be noted that other devices and/or systems of devices,such as remote computer(s), provide both input and output capabilities.

The computer system 210 can operate in a networked environment usinglogical connections to one or more remote computers, such as cloudcomputer(s), or local computers. The remote cloud computer(s) can be apersonal computer, server, router, network PC, workstation,microprocessor-based appliance, peer device, or other common networknode, and the like, and typically includes many or all of the elementsdescribed relative to the computer system. For purposes of brevity, onlya memory storage device is illustrated with the remote computer(s). Theremote computer(s) is logically connected to the computer system througha network interface and then physically connected via a communicationconnection. The network interface encompasses communication networkssuch as local area networks (LANs) and wide area networks (WANs). LANtechnologies include Fiber Distributed Data Interface (FDDI), CopperDistributed Data Interface (CDDI), Ethernet/IEEE 802.3, Token Ring/IEEE802.5 and the like. WAN technologies include, but are not limited to,point-to-point links, circuit-switching networks like IntegratedServices Digital Networks (ISDN) and variations thereon,packet-switching networks, and Digital Subscriber Lines (DSL).

In various aspects, the computer system 210 of FIG. 10 , the imagingmodule 238 and/or visualization system 208, and/or the processor module232 of FIGS. 9-10 , may comprise an image processor, image-processingengine, media processor, or any specialized digital signal processor(DSP) used for the processing of digital images. The image processor mayemploy parallel computing with single instruction, multiple data (SIMD)or multiple instruction, multiple data (MIMD) technologies to increasespeed and efficiency. The digital image-processing engine can perform arange of tasks. The image processor may be a system on a chip withmulticore processor architecture.

The communication connection(s) refers to the hardware/software employedto connect the network interface to the bus. While the communicationconnection is shown for illustrative clarity inside the computer system,it can also be external to the computer system 210. Thehardware/software necessary for connection to the network interfaceincludes, for illustrative purposes only, internal and externaltechnologies such as modems, including regular telephone-grade modems,cable modems, and DSL modems, ISDN adapters, and Ethernet cards.

FIG. 11 illustrates a functional block diagram of one aspect of a USBnetwork hub 300 device, in accordance with at least one aspect of thepresent disclosure. In the illustrated aspect, the USB network hubdevice 300 employs a TUSB2036 integrated circuit hub by TexasInstruments. The USB network hub 300 is a CMOS device that provides anupstream USB transceiver port 302 and up to three downstream USBtransceiver ports 304, 306, 308 in compliance with the USB 2.0specification. The upstream USB transceiver port 302 is a differentialroot data port comprising a differential data minus (DM0) input pairedwith a differential data plus (DP0) input. The three downstream USBtransceiver ports 304, 306, 308 are differential data ports where eachport includes differential data plus (DP1-DP3) outputs paired withdifferential data minus (DM1-DM3) outputs.

The USB network hub 300 device is implemented with a digital statemachine instead of a microcontroller, and no firmware programming isrequired. Fully compliant USB transceivers are integrated into thecircuit for the upstream USB transceiver port 302 and all downstream USBtransceiver ports 304, 306, 308. The downstream USB transceiver ports304, 306, 308 support both full-speed and low-speed devices byautomatically setting the slew rate according to the speed of the deviceattached to the ports. The USB network hub 300 device may be configuredeither in bus-powered or self-powered mode and includes a hub powerlogic 312 to manage power.

The USB network hub 300 device includes a serial interface engine 310(SIE). The SIE 310 is the front end of the USB network hub 300 hardwareand handles most of the protocol described in chapter 8 of the USBspecification. The SIE 310 typically comprehends signaling up to thetransaction level. The functions that it handles could include: packetrecognition, transaction sequencing, SOP, EOP, RESET, and RESUME signaldetection/generation, clock/data separation, non-return-to-zero invert(NRZI) data encoding/decoding and bit-stuffing, CRC generation andchecking (token and data), packet ID (PID) generation andchecking/decoding, and/or serial-parallel/parallel-serial conversion.The 310 receives a clock input 314 and is coupled to a suspend/resumelogic and frame timer 316 circuit and a hub repeater circuit 318 tocontrol communication between the upstream USB transceiver port 302 andthe downstream USB transceiver ports 304, 306, 308 through port logiccircuits 320, 322, 324. The SIE 310 is coupled to a command decoder 326via interface logic to control commands from a serial EEPROM via aserial EEPROM interface 330.

In various aspects, the USB network hub 300 can connect 127 functionsconfigured in up to six logical layers (tiers) to a single computer.Further, the USB network hub 300 can connect to all peripherals using astandardized four-wire cable that provides both communication and powerdistribution. The power configurations are bus-powered and self-poweredmodes. The USB network hub 300 may be configured to support four modesof power management: a bus-powered hub, with either individual-portpower management or ganged-port power management, and the self-poweredhub, with either individual-port power management or ganged-port powermanagement. In one aspect, using a USB cable, the USB network hub 300,the upstream USB transceiver port 302 is plugged into a USB hostcontroller, and the downstream USB transceiver ports 304, 306, 308 areexposed for connecting USB compatible devices, and so forth.

Surgical Instrument Hardware

FIG. 12 illustrates a logic diagram of a control system 470 of asurgical instrument or tool in accordance with one or more aspects ofthe present disclosure. The system 470 comprises a control circuit. Thecontrol circuit includes a microcontroller 461 comprising a processor462 and a memory 468. One or more of sensors 472, 474, 476, for example,provide real-time feedback to the processor 462. A motor 482, driven bya motor driver 492, operably couples a longitudinally movabledisplacement member to drive a clamp arm closure member. A trackingsystem 480 is configured to determine the position of the longitudinallymovable displacement member. The position information is provided to theprocessor 462, which can be programmed or configured to determine theposition of the longitudinally movable drive member as well as theposition of the closure member. Additional motors may be provided at thetool driver interface to control closure tube travel, shaft rotation,articulation, or clamp arm closure, or a combination of the above. Adisplay 473 displays a variety of operating conditions of theinstruments and may include touch screen functionality for data input.Information displayed on the display 473 may be overlaid with imagesacquired via endoscopic imaging modules.

In one aspect, the microcontroller 461 may be any single-core ormulticore processor such as those known under the trade name ARM Cortexby Texas Instruments. In one aspect, the main microcontroller 461 may bean LM4F230H5QR ARM Cortex-M4F Processor Core, available from TexasInstruments, for example, comprising an on-chip memory of 256 KBsingle-cycle flash memory, or other non-volatile memory, up to 40 MHz, aprefetch buffer to improve performance above 40 MHz, a 32 KBsingle-cycle SRAM, and internal ROM loaded with StellarisWare® software,a 2 KB EEPROM, one or more PWM modules, one or more QEI analogs, and/orone or more 12-bit ADCs with 12 analog input channels, details of whichare available for the product datasheet.

In one aspect, the microcontroller 461 may comprise a safety controllercomprising two controller-based families such as TMS570 and RM4x, knownunder the trade name Hercules ARM Cortex R4, also by Texas Instruments.The safety controller may be configured specifically for IEC 61508 andISO 26262 safety critical applications, among others, to provideadvanced integrated safety features while delivering scalableperformance, connectivity, and memory options.

The microcontroller 461 may be programmed to perform various functionssuch as precise control over the speed and position of the knife,articulation systems, clamp arm, or a combination of the above. In oneaspect, the microcontroller 461 includes a processor 462 and a memory468. The electric motor 482 may be a brushed direct current (DC) motorwith a gearbox and mechanical links to an articulation or knife system.In one aspect, a motor driver 492 may be an A3941 available from AllegroMicrosystems, Inc. Other motor drivers may be readily substituted foruse in the tracking system 480 comprising an absolute positioningsystem. A detailed description of an absolute positioning system isdescribed in U.S. Patent Application Publication No. 2017/0296213,titled SYSTEMS AND METHODS FOR CONTROLLING A SURGICAL STAPLING ANDCUTTING INSTRUMENT, which published on Oct. 19, 2017, which is hereinincorporated by reference in its entirety.

The microcontroller 461 may be programmed to provide precise controlover the speed and position of displacement members and articulationsystems. The microcontroller 461 may be configured to compute a responsein the software of the microcontroller 461. The computed response iscompared to a measured response of the actual system to obtain an“observed” response, which is used for actual feedback decisions. Theobserved response is a favorable, tuned value that balances the smooth,continuous nature of the simulated response with the measured response,which can detect outside influences on the system.

In one aspect, the motor 482 may be controlled by the motor driver 492and can be employed by the firing system of the surgical instrument ortool. In various forms, the motor 482 may be a brushed DC driving motorhaving a maximum rotational speed of approximately 25,000 RPM. In otherarrangements, the motor 482 may include a brushless motor, a cordlessmotor, a synchronous motor, a stepper motor, or any other suitableelectric motor. The motor driver 492 may comprise an H-bridge drivercomprising field-effect transistors (FETs), for example. The motor 482can be powered by a power assembly releasably mounted to the handleassembly or tool housing for supplying control power to the surgicalinstrument or tool. The power assembly may comprise a battery which mayinclude a number of battery cells connected in series that can be usedas the power source to power the surgical instrument or tool. In certaincircumstances, the battery cells of the power assembly may bereplaceable and/or rechargeable battery cells. In at least one example,the battery cells can be lithium-ion batteries which can be couplable toand separable from the power assembly.

The motor driver 492 may be an A3941 available from AllegroMicrosystems, Inc. The A3941 492 is a full-bridge controller for usewith external N-channel power metal-oxide semiconductor field-effecttransistors (MOSFETs) specifically designed for inductive loads, such asbrush DC motors. The driver 492 comprises a unique charge pump regulatorthat provides full (>10 V) gate drive for battery voltages down to 7 Vand allows the A3941 to operate with a reduced gate drive, down to 5.5V. A bootstrap capacitor may be employed to provide the above batterysupply voltage required for N-channel MOSFETs. An internal charge pumpfor the high-side drive allows DC (100% duty cycle) operation. The fullbridge can be driven in fast or slow decay modes using diode orsynchronous rectification. In the slow decay mode, current recirculationcan be through the high-side or the low-side FETs. The power FETs areprotected from shoot-through by resistor-adjustable dead time.Integrated diagnostics provide indications of undervoltage,overtemperature, and power bridge faults and can be configured toprotect the power MOSFETs under most short circuit conditions. Othermotor drivers may be readily substituted for use in the tracking system480 comprising an absolute positioning system.

The tracking system 480 comprises a controlled motor drive circuitarrangement comprising a position sensor 472 according to one aspect ofthis disclosure. The position sensor 472 for an absolute positioningsystem provides a unique position signal corresponding to the locationof a displacement member. In one aspect, the displacement memberrepresents a longitudinally movable drive member comprising a rack ofdrive teeth for meshing engagement with a corresponding drive gear of agear reducer assembly. In other aspects, the displacement memberrepresents the firing member, which could be adapted and configured toinclude a rack of drive teeth. In yet another aspect, the displacementmember represents a longitudinal displacement member to open and close aclamp arm, which can be adapted and configured to include a rack ofdrive teeth. In other aspects, the displacement member represents aclamp arm closure member configured to close and to open a clamp arm ofa stapler, ultrasonic, or electrosurgical device, or combinations of theabove. Accordingly, as used herein, the term displacement member is usedgenerically to refer to any movable member of the surgical instrument ortool such as the drive member, the clamp arm, or any element that can bedisplaced. Accordingly, the absolute positioning system can, in effect,track the displacement of the clamp arm by tracking the lineardisplacement of the longitudinally movable drive member.

In other aspects, the absolute positioning system can be configured totrack the position of a clamp arm in the process of closing or opening.In various other aspects, the displacement member may be coupled to anyposition sensor 472 suitable for measuring linear displacement. Thus,the longitudinally movable drive member, or clamp arm, or combinationsthereof, may be coupled to any suitable linear displacement sensor.Linear displacement sensors may include contact or non-contactdisplacement sensors. Linear displacement sensors may comprise linearvariable differential transformers (LVDT), differential variablereluctance transducers (DVRT), a slide potentiometer, a magnetic sensingsystem comprising a movable magnet and a series of linearly arrangedHall effect sensors, a magnetic sensing system comprising a fixed magnetand a series of movable, linearly arranged Hall effect sensors, anoptical sensing system comprising a movable light source and a series oflinearly arranged photo diodes or photo detectors, an optical sensingsystem comprising a fixed light source and a series of movable linearly,arranged photo diodes or photo detectors, or any combination thereof.

The electric motor 482 can include a rotatable shaft that operablyinterfaces with a gear assembly that is mounted in meshing engagementwith a set, or rack, of drive teeth on the displacement member. A sensorelement may be operably coupled to a gear assembly such that a singlerevolution of the position sensor 472 element corresponds to some linearlongitudinal translation of the displacement member. An arrangement ofgearing and sensors can be connected to the linear actuator, via a rackand pinion arrangement, or a rotary actuator, via a spur gear or otherconnection. A power source supplies power to the absolute positioningsystem and an output indicator may display the output of the absolutepositioning system. The displacement member represents thelongitudinally movable drive member comprising a rack of drive teethformed thereon for meshing engagement with a corresponding drive gear ofthe gear reducer assembly. The displacement member represents thelongitudinally movable firing member to open and close a clamp arm.

A single revolution of the sensor element associated with the positionsensor 472 is equivalent to a longitudinal linear displacement d₁ of theof the displacement member, where d₁ is the longitudinal linear distancethat the displacement member moves from point “a” to point “b” after asingle revolution of the sensor element coupled to the displacementmember. The sensor arrangement may be connected via a gear reductionthat results in the position sensor 472 completing one or morerevolutions for the full stroke of the displacement member. The positionsensor 472 may complete multiple revolutions for the full stroke of thedisplacement member.

A series of switches, where n is an integer greater than one, may beemployed alone or in combination with a gear reduction to provide aunique position signal for more than one revolution of the positionsensor 472. The state of the switches are fed back to themicrocontroller 461 that applies logic to determine a unique positionsignal corresponding to the longitudinal linear displacement d₁+d₂+ . .. d_(n) of the displacement member. The output of the position sensor472 is provided to the microcontroller 461. The position sensor 472 ofthe sensor arrangement may comprise a magnetic sensor, an analog rotarysensor like a potentiometer, or an array of analog Hall-effect elements,which output a unique combination of position signals or values.

The position sensor 472 may comprise any number of magnetic sensingelements, such as, for example, magnetic sensors classified according towhether they measure the total magnetic field or the vector componentsof the magnetic field. The techniques used to produce both types ofmagnetic sensors encompass many aspects of physics and electronics. Thetechnologies used for magnetic field sensing include search coil,fluxgate, optically pumped, nuclear precession, SQUID, Hall-effect,anisotropic magnetoresistance, giant magnetoresistance, magnetic tunneljunctions, giant magnetoimpedance, magnetostrictive/piezoelectriccomposites, magnetodiode, magnetotransistor, fiber-optic, magneto-optic,and microelectromechanical systems-based magnetic sensors, among others.

In one aspect, the position sensor 472 for the tracking system 480comprising an absolute positioning system comprises a magnetic rotaryabsolute positioning system. The position sensor 472 may be implementedas an AS5055EQFT single-chip magnetic rotary position sensor availablefrom Austria Microsystems, AG. The position sensor 472 is interfacedwith the microcontroller 461 to provide an absolute positioning system.The position sensor 472 is a low-voltage and low-power component andincludes four Hall-effect elements in an area of the position sensor 472that is located above a magnet. A high-resolution ADC and a smart powermanagement controller are also provided on the chip. A coordinaterotation digital computer (CORDIC) processor, also known as thedigit-by-digit method and Volder's algorithm, is provided to implement asimple and efficient algorithm to calculate hyperbolic and trigonometricfunctions that require only addition, subtraction, bitshift, and tablelookup operations. The angle position, alarm bits, and magnetic fieldinformation are transmitted over a standard serial communicationinterface, such as a serial peripheral interface (SPI) interface, to themicrocontroller 461. The position sensor 472 provides 12 or 14 bits ofresolution. The position sensor 472 may be an AS5055 chip provided in asmall QFN 16-pin 4×4×0.85 mm package.

The tracking system 480 comprising an absolute positioning system maycomprise and/or be programmed to implement a feedback controller, suchas a PID, state feedback, and adaptive controller. A power sourceconverts the signal from the feedback controller into a physical inputto the system: in this case the voltage. Other examples include a PWM ofthe voltage, current, and force. Other sensor(s) may be provided tomeasure physical parameters of the physical system in addition to theposition measured by the position sensor 472. In some aspects, the othersensor(s) can include sensor arrangements such as those described inU.S. Pat. No. 9,345,481, titled STAPLE CARTRIDGE TISSUE THICKNESS SENSORSYSTEM, which issued on May 24, 2016, which is herein incorporated byreference in its entirety; U.S. Patent Application Publication No.2014/0263552, titled STAPLE CARTRIDGE TISSUE THICKNESS SENSOR SYSTEM,which published on Sep. 18, 2014, which is herein incorporated byreference in its entirety; and U.S. patent application Ser. No.15/628,175, titled TECHNIQUES FOR ADAPTIVE CONTROL OF MOTOR VELOCITY OFA SURGICAL STAPLING AND CUTTING INSTRUMENT, filed Jun. 20, 2017, whichis herein incorporated by reference in its entirety. In a digital signalprocessing system, an absolute positioning system is coupled to adigital data acquisition system where the output of the absolutepositioning system will have a finite resolution and sampling frequency.The absolute positioning system may comprise a compare-and-combinecircuit to combine a computed response with a measured response usingalgorithms, such as a weighted average and a theoretical control loop,that drive the computed response towards the measured response. Thecomputed response of the physical system takes into account propertieslike mass, inertia, viscous friction, inductance resistance, etc., topredict what the states and outputs of the physical system will be byknowing the input.

The absolute positioning system provides an absolute position of thedisplacement member upon power-up of the instrument, without retractingor advancing the displacement member to a reset (zero or home) positionas may be required with conventional rotary encoders that merely countthe number of steps forwards or backwards that the motor 482 has takento infer the position of a device actuator, drive bar, knife, or thelike.

A sensor 474, such as, for example, a strain gauge or a micro-straingauge, is configured to measure one or more parameters of the endeffector, such as, for example, the amplitude of the strain exerted onthe anvil during a clamping operation, which can be indicative of theclosure forces applied to the anvil. The measured strain is converted toa digital signal and provided to the processor 462. Alternatively, or inaddition to the sensor 474, a sensor 476, such as, for example, a loadsensor, can measure the closure force applied by the closure drivesystem to the anvil in a stapler or a clamp arm in an ultrasonic orelectrosurgical instrument. The sensor 476, such as, for example, a loadsensor, can measure the firing force applied to a closure member coupledto a clamp arm of the surgical instrument or tool or the force appliedby a clamp arm to tissue located in the jaws of an ultrasonic orelectrosurgical instrument. Alternatively, a current sensor 478 can beemployed to measure the current drawn by the motor 482. The displacementmember also may be configured to engage a clamp arm to open or close theclamp arm. The force sensor may be configured to measure the clampingforce on tissue. The force required to advance the displacement membercan correspond to the current drawn by the motor 482, for example. Themeasured force is converted to a digital signal and provided to theprocessor 462.

In one form, the strain gauge sensor 474 can be used to measure theforce applied to the tissue by the end effector. A strain gauge can becoupled to the end effector to measure the force on the tissue beingtreated by the end effector. A system for measuring forces applied tothe tissue grasped by the end effector comprises a strain gauge sensor474, such as, for example, a micro-strain gauge, that is configured tomeasure one or more parameters of the end effector, for example. In oneaspect, the strain gauge sensor 474 can measure the amplitude ormagnitude of the strain exerted on a jaw member of an end effectorduring a clamping operation, which can be indicative of the tissuecompression. The measured strain is converted to a digital signal andprovided to a processor 462 of the microcontroller 461. A load sensor476 can measure the force used to operate the knife element, forexample, to cut the tissue captured between the anvil and the staplecartridge. A load sensor 476 can measure the force used to operate theclamp arm element, for example, to capture tissue between the clamp armand an ultrasonic blade or to capture tissue between the clamp arm and ajaw of an electrosurgical instrument. A magnetic field sensor can beemployed to measure the thickness of the captured tissue. Themeasurement of the magnetic field sensor also may be converted to adigital signal and provided to the processor 462.

The measurements of the tissue compression, the tissue thickness, and/orthe force required to close the end effector on the tissue, asrespectively measured by the sensors 474, 476, can be used by themicrocontroller 461 to characterize the selected position of the firingmember and/or the corresponding value of the speed of the firing member.In one instance, a memory 468 may store a technique, an equation, and/ora lookup table which can be employed by the microcontroller 461 in theassessment.

The control system 470 of the surgical instrument or tool also maycomprise wired or wireless communication circuits to communicate withthe modular communication hub as shown in FIGS. 8-11 .

FIG. 13 illustrates a control circuit 500 configured to control aspectsof the surgical instrument or tool according to one aspect of thisdisclosure. The control circuit 500 can be configured to implementvarious processes described herein. The control circuit 500 may comprisea microcontroller comprising one or more processors 502 (e.g.,microprocessor, microcontroller) coupled to at least one memory circuit504. The memory circuit 504 stores machine-executable instructions that,when executed by the processor 502, cause the processor 502 to executemachine instructions to implement various processes described herein.The processor 502 may be any one of a number of single-core or multicoreprocessors known in the art. The memory circuit 504 may comprisevolatile and non-volatile storage media. The processor 502 may includean instruction processing unit 506 and an arithmetic unit 508. Theinstruction processing unit may be configured to receive instructionsfrom the memory circuit 504 of this disclosure.

FIG. 14 illustrates a combinational logic circuit 510 configured tocontrol aspects of the surgical instrument or tool according to oneaspect of this disclosure. The combinational logic circuit 510 can beconfigured to implement various processes described herein. Thecombinational logic circuit 510 may comprise a finite state machinecomprising a combinational logic 512 configured to receive dataassociated with the surgical instrument or tool at an input 514, processthe data by the combinational logic 512, and provide an output 516.

FIG. 15 illustrates a sequential logic circuit 520 configured to controlaspects of the surgical instrument or tool according to one aspect ofthis disclosure. The sequential logic circuit 520 or the combinationallogic 522 can be configured to implement various processes describedherein. The sequential logic circuit 520 may comprise a finite statemachine. The sequential logic circuit 520 may comprise a combinationallogic 522, at least one memory circuit 524, and a clock 529, forexample. The at least one memory circuit 524 can store a current stateof the finite state machine. In certain instances, the sequential logiccircuit 520 may be synchronous or asynchronous. The combinational logic522 is configured to receive data associated with the surgicalinstrument or tool from an input 526, process the data by thecombinational logic 522, and provide an output 528. In other aspects,the circuit may comprise a combination of a processor (e.g., processor502, FIG. 13 ) and a finite state machine to implement various processesherein. In other aspects, the finite state machine may comprise acombination of a combinational logic circuit (e.g., combinational logiccircuit 510, FIG. 14 ) and the sequential logic circuit 520.

FIG. 16 illustrates a surgical instrument or tool comprising a pluralityof motors which can be activated to perform various functions. Incertain instances, a first motor can be activated to perform a firstfunction, a second motor can be activated to perform a second function,a third motor can be activated to perform a third function, a fourthmotor can be activated to perform a fourth function, and so on. Incertain instances, the plurality of motors of robotic surgicalinstrument 600 can be individually activated to cause firing, closure,and/or articulation motions in the end effector. The firing, closure,and/or articulation motions can be transmitted to the end effectorthrough a shaft assembly, for example.

In certain instances, the surgical instrument system or tool may includea firing motor 602. The firing motor 602 may be operably coupled to afiring motor drive assembly 604 which can be configured to transmitfiring motions, generated by the motor 602 to the end effector, inparticular to displace the clamp arm closure member. The closure membermay be retracted by reversing the direction of the motor 602, which alsocauses the clamp arm to open.

In certain instances, the surgical instrument or tool may include aclosure motor 603. The closure motor 603 may be operably coupled to aclosure motor drive assembly 605 which can be configured to transmitclosure motions, generated by the motor 603 to the end effector, inparticular to displace a closure tube to close the anvil and compresstissue between the anvil and the staple cartridge. The closure motor 603may be operably coupled to a closure motor drive assembly 605 which canbe configured to transmit closure motions, generated by the motor 603 tothe end effector, in particular to displace a closure tube to close theclamp arm and compress tissue between the clamp arm and either anultrasonic blade or jaw member of an electrosurgical device. The closuremotions may cause the end effector to transition from an openconfiguration to an approximated configuration to capture tissue, forexample. The end effector may be transitioned to an open position byreversing the direction of the motor 603.

In certain instances, the surgical instrument or tool may include one ormore articulation motors 606 a, 606 b, for example. The motors 606 a,606 b may be operably coupled to respective articulation motor driveassemblies 608 a, 608 b, which can be configured to transmitarticulation motions generated by the motors 606 a, 606 b to the endeffector. In certain instances, the articulation motions may cause theend effector to articulate relative to the shaft, for example.

As described above, the surgical instrument or tool may include aplurality of motors which may be configured to perform variousindependent functions. In certain instances, the plurality of motors ofthe surgical instrument or tool can be individually or separatelyactivated to perform one or more functions while the other motors remaininactive. For example, the articulation motors 606 a, 606 b can beactivated to cause the end effector to be articulated while the firingmotor 602 remains inactive. Alternatively, the firing motor 602 can beactivated to fire the plurality of staples, and/or to advance thecutting edge, while the articulation motor 606 remains inactive.Furthermore, the closure motor 603 may be activated simultaneously withthe firing motor 602 to cause the closure tube or closure member toadvance distally as described in more detail hereinbelow.

In certain instances, the surgical instrument or tool may include acommon control module 610 which can be employed with a plurality ofmotors of the surgical instrument or tool. In certain instances, thecommon control module 610 may accommodate one of the plurality of motorsat a time. For example, the common control module 610 can be couplableto and separable from the plurality of motors of the robotic surgicalinstrument individually. In certain instances, a plurality of the motorsof the surgical instrument or tool may share one or more common controlmodules such as the common control module 610. In certain instances, aplurality of motors of the surgical instrument or tool can beindividually and selectively engaged with the common control module 610.In certain instances, the common control module 610 can be selectivelyswitched from interfacing with one of a plurality of motors of thesurgical instrument or tool to interfacing with another one of theplurality of motors of the surgical instrument or tool.

In at least one example, the common control module 610 can beselectively switched between operable engagement with the articulationmotors 606 a, 606 b and operable engagement with either the firing motor602 or the closure motor 603. In at least one example, as illustrated inFIG. 16 , a switch 614 can be moved or transitioned between a pluralityof positions and/or states. In a first position 616, the switch 614 mayelectrically couple the common control module 610 to the firing motor602; in a second position 617, the switch 614 may electrically couplethe common control module 610 to the closure motor 603; in a thirdposition 618 a, the switch 614 may electrically couple the commoncontrol module 610 to the first articulation motor 606 a; and in afourth position 618 b, the switch 614 may electrically couple the commoncontrol module 610 to the second articulation motor 606 b, for example.In certain instances, separate common control modules 610 can beelectrically coupled to the firing motor 602, the closure motor 603, andthe articulations motor 606 a, 606 b at the same time. In certaininstances, the switch 614 may be a mechanical switch, anelectromechanical switch, a solid-state switch, or any suitableswitching mechanism.

Each of the motors 602, 603, 606 a, 606 b may comprise a torque sensorto measure the output torque on the shaft of the motor. The force on anend effector may be sensed in any conventional manner, such as by forcesensors on the outer sides of the jaws or by a torque sensor for themotor actuating the jaws.

In various instances, as illustrated in FIG. 16 , the common controlmodule 610 may comprise a motor driver 626 which may comprise one ormore H-Bridge FETs. The motor driver 626 may modulate the powertransmitted from a power source 628 to a motor coupled to the commoncontrol module 610 based on input from a microcontroller 620 (the“controller”), for example. In certain instances, the microcontroller620 can be employed to determine the current drawn by the motor, forexample, while the motor is coupled to the common control module 610, asdescribed above.

In certain instances, the microcontroller 620 may include amicroprocessor 622 (the “processor”) and one or more non-transitorycomputer-readable mediums or memory units 624 (the “memory”). In certaininstances, the memory 624 may store various program instructions, whichwhen executed may cause the processor 622 to perform a plurality offunctions and/or calculations described herein. In certain instances,one or more of the memory units 624 may be coupled to the processor 622,for example. In various aspects, the microcontroller 620 may communicateover a wired or wireless channel, or combinations thereof.

In certain instances, the power source 628 can be employed to supplypower to the microcontroller 620, for example. In certain instances, thepower source 628 may comprise a battery (or “battery pack” or “powerpack”), such as a lithium-ion battery, for example. In certaininstances, the battery pack may be configured to be releasably mountedto a handle for supplying power to the surgical instrument 600. A numberof battery cells connected in series may be used as the power source628. In certain instances, the power source 628 may be replaceableand/or rechargeable, for example.

In various instances, the processor 622 may control the motor driver 626to control the position, direction of rotation, and/or velocity of amotor that is coupled to the common control module 610. In certaininstances, the processor 622 can signal the motor driver 626 to stopand/or disable a motor that is coupled to the common control module 610.It should be understood that the term “processor” as used hereinincludes any suitable microprocessor, microcontroller, or other basiccomputing device that incorporates the functions of a computer's centralprocessing unit (CPU) on an integrated circuit or, at most, a fewintegrated circuits. The processor 622 is a multipurpose, programmabledevice that accepts digital data as input, processes it according toinstructions stored in its memory, and provides results as output. It isan example of sequential digital logic, as it has internal memory.Processors operate on numbers and symbols represented in the binarynumeral system.

In one instance, the processor 622 may be any single-core or multicoreprocessor such as those known under the trade name ARM Cortex by TexasInstruments. In certain instances, the microcontroller 620 may be an LM4F230H5QR, available from Texas Instruments, for example. In at leastone example, the Texas Instruments LM4F230H5QR is an ARM Cortex-M4FProcessor Core comprising an on-chip memory of 256 KB single-cycle flashmemory, or other non-volatile memory, up to 40 MHz, a prefetch buffer toimprove performance above 40 MHz, a 32 KB single-cycle SRAM, an internalROM loaded with StellarisWare® software, a 2 KB EEPROM, one or more PWMmodules, one or more QEI analogs, one or more 12-bit ADCs with 12 analoginput channels, among other features that are readily available for theproduct datasheet. Other microcontrollers may be readily substituted foruse with the module 4410. Accordingly, the present disclosure should notbe limited in this context.

In certain instances, the memory 624 may include program instructionsfor controlling each of the motors of the surgical instrument 600 thatare couplable to the common control module 610. For example, the memory624 may include program instructions for controlling the firing motor602, the closure motor 603, and the articulation motors 606 a, 606 b.Such program instructions may cause the processor 622 to control thefiring, closure, and articulation functions in accordance with inputsfrom algorithms or control programs of the surgical instrument or tool.

In certain instances, one or more mechanisms and/or sensors such as, forexample, sensors 630 can be employed to alert the processor 622 to theprogram instructions that should be used in a particular setting. Forexample, the sensors 630 may alert the processor 622 to use the programinstructions associated with firing, closing, and articulating the endeffector. In certain instances, the sensors 630 may comprise positionsensors which can be employed to sense the position of the switch 614,for example. Accordingly, the processor 622 may use the programinstructions associated with firing the closure member coupled to theclamp arm of the end effector upon detecting, through the sensors 630for example, that the switch 614 is in the first position 616; theprocessor 622 may use the program instructions associated with closingthe anvil upon detecting, through the sensors 630 for example, that theswitch 614 is in the second position 617; and the processor 622 may usethe program instructions associated with articulating the end effectorupon detecting, through the sensors 630 for example, that the switch 614is in the third or fourth position 618 a, 618 b.

FIG. 17 is a schematic diagram of a robotic surgical instrument 700configured to operate a surgical tool described herein according to oneaspect of this disclosure. The robotic surgical instrument 700 may beprogrammed or configured to control distal/proximal translation of adisplacement member, distal/proximal displacement of a closure tube,shaft rotation, and articulation, either with single or multiplearticulation drive links. In one aspect, the surgical instrument 700 maybe programmed or configured to individually control a firing member, aclosure member, a shaft member, or one or more articulation members, orcombinations thereof. The surgical instrument 700 comprises a controlcircuit 710 configured to control motor-driven firing members, closuremembers, shaft members, or one or more articulation members, orcombinations thereof.

In one aspect, the robotic surgical instrument 700 comprises a controlcircuit 710 configured to control a clamp arm 716 and a closure member714 portion of an end effector 702, an ultrasonic blade 718 coupled toan ultrasonic transducer 719 excited by an ultrasonic generator 721, ashaft 740, and one or more articulation members 742 a, 742 b via aplurality of motors 704 a-704 e. A position sensor 734 may be configuredto provide position feedback of the closure member 714 to the controlcircuit 710. Other sensors 738 may be configured to provide feedback tothe control circuit 710. A timer/counter 731 provides timing andcounting information to the control circuit 710. An energy source 712may be provided to operate the motors 704 a-704 e, and a current sensor736 provides motor current feedback to the control circuit 710. Themotors 704 a-704 e can be operated individually by the control circuit710 in an open-loop or closed-loop feedback control.

In one aspect, the control circuit 710 may comprise one or moremicrocontrollers, microprocessors, or other suitable processors forexecuting instructions that cause the processor or processors to performone or more tasks. In one aspect, a timer/counter 731 provides an outputsignal, such as the elapsed time or a digital count, to the controlcircuit 710 to correlate the position of the closure member 714 asdetermined by the position sensor 734 with the output of thetimer/counter 731 such that the control circuit 710 can determine theposition of the closure member 714 at a specific time (t) relative to astarting position or the time (t) when the closure member 714 is at aspecific position relative to a starting position. The timer/counter 731may be configured to measure elapsed time, count external events, ortime external events.

In one aspect, the control circuit 710 may be programmed to controlfunctions of the end effector 702 based on one or more tissueconditions. The control circuit 710 may be programmed to sense tissueconditions, such as thickness, either directly or indirectly, asdescribed herein. The control circuit 710 may be programmed to select afiring control program or closure control program based on tissueconditions. A firing control program may describe the distal motion ofthe displacement member. Different firing control programs may beselected to better treat different tissue conditions. For example, whenthicker tissue is present, the control circuit 710 may be programmed totranslate the displacement member at a lower velocity and/or with lowerpower. When thinner tissue is present, the control circuit 710 may beprogrammed to translate the displacement member at a higher velocityand/or with higher power. A closure control program may control theclosure force applied to the tissue by the clamp arm 716. Other controlprograms control the rotation of the shaft 740 and the articulationmembers 742 a, 742 b.

In one aspect, the control circuit 710 may generate motor set pointsignals. The motor set point signals may be provided to various motorcontrollers 708 a-708 e. The motor controllers 708 a-708 e may compriseone or more circuits configured to provide motor drive signals to themotors 704 a-704 e to drive the motors 704 a-704 e as described herein.In some examples, the motors 704 a-704 e may be brushed DC electricmotors. For example, the velocity of the motors 704 a-704 e may beproportional to the respective motor drive signals. In some examples,the motors 704 a-704 e may be brushless DC electric motors, and therespective motor drive signals may comprise a PWM signal provided to oneor more stator windings of the motors 704 a-704 e. Also, in someexamples, the motor controllers 708 a-708 e may be omitted and thecontrol circuit 710 may generate the motor drive signals directly.

In one aspect, the control circuit 710 may initially operate each of themotors 704 a-704 e in an open-loop configuration for a first open-loopportion of a stroke of the displacement member. Based on the response ofthe robotic surgical instrument 700 during the open-loop portion of thestroke, the control circuit 710 may select a firing control program in aclosed-loop configuration. The response of the instrument may include atranslation distance of the displacement member during the open-loopportion, a time elapsed during the open-loop portion, the energyprovided to one of the motors 704 a-704 e during the open-loop portion,a sum of pulse widths of a motor drive signal, etc. After the open-loopportion, the control circuit 710 may implement the selected firingcontrol program for a second portion of the displacement member stroke.For example, during a closed-loop portion of the stroke, the controlcircuit 710 may modulate one of the motors 704 a-704 e based ontranslation data describing a position of the displacement member in aclosed-loop manner to translate the displacement member at a constantvelocity.

In one aspect, the motors 704 a-704 e may receive power from an energysource 712. The energy source 712 may be a DC power supply driven by amain alternating current power source, a battery, a super capacitor, orany other suitable energy source. The motors 704 a-704 e may bemechanically coupled to individual movable mechanical elements such asthe closure member 714, clamp arm 716, shaft 740, articulation 742 a,and articulation 742 b via respective transmissions 706 a-706 e. Thetransmissions 706 a-706 e may include one or more gears or other linkagecomponents to couple the motors 704 a-704 e to movable mechanicalelements. A position sensor 734 may sense a position of the closuremember 714. The position sensor 734 may be or include any type of sensorthat is capable of generating position data that indicate a position ofthe closure member 714. In some examples, the position sensor 734 mayinclude an encoder configured to provide a series of pulses to thecontrol circuit 710 as the closure member 714 translates distally andproximally. The control circuit 710 may track the pulses to determinethe position of the closure member 714. Other suitable position sensorsmay be used, including, for example, a proximity sensor. Other types ofposition sensors may provide other signals indicating motion of theclosure member 714. Also, in some examples, the position sensor 734 maybe omitted. Where any of the motors 704 a-704 e is a stepper motor, thecontrol circuit 710 may track the position of the closure member 714 byaggregating the number and direction of steps that the motor 704 hasbeen instructed to execute. The position sensor 734 may be located inthe end effector 702 or at any other portion of the instrument. Theoutputs of each of the motors 704 a-704 e include a torque sensor 744a-744 e to sense force and have an encoder to sense rotation of thedrive shaft.

In one aspect, the control circuit 710 is configured to drive a firingmember such as the closure member 714 portion of the end effector 702.The control circuit 710 provides a motor set point to a motor control708 a, which provides a drive signal to the motor 704 a. The outputshaft of the motor 704 a is coupled to a torque sensor 744 a. The torquesensor 744 a is coupled to a transmission 706 a which is coupled to theclosure member 714. The transmission 706 a comprises movable mechanicalelements such as rotating elements and a firing member to control themovement of the closure member 714 distally and proximally along alongitudinal axis of the end effector 702. In one aspect, the motor 704a may be coupled to the knife gear assembly, which includes a knife gearreduction set that includes a first knife drive gear and a second knifedrive gear. A torque sensor 744 a provides a firing force feedbacksignal to the control circuit 710. The firing force signal representsthe force required to fire or displace the closure member 714. Aposition sensor 734 may be configured to provide the position of theclosure member 714 along the firing stroke or the position of the firingmember as a feedback signal to the control circuit 710. The end effector702 may include additional sensors 738 configured to provide feedbacksignals to the control circuit 710. When ready to use, the controlcircuit 710 may provide a firing signal to the motor control 708 a. Inresponse to the firing signal, the motor 704 a may drive the firingmember distally along the longitudinal axis of the end effector 702 froma proximal stroke start position to a stroke end position distal to thestroke start position. As the closure member 714 translates distally,the clamp arm 716 closes towards the ultrasonic blade 718.

In one aspect, the control circuit 710 is configured to drive a closuremember such as the clamp arm 716 portion of the end effector 702. Thecontrol circuit 710 provides a motor set point to a motor control 708 b,which provides a drive signal to the motor 704 b. The output shaft ofthe motor 704 b is coupled to a torque sensor 744 b. The torque sensor744 b is coupled to a transmission 706 b which is coupled to the clamparm 716. The transmission 706 b comprises movable mechanical elementssuch as rotating elements and a closure member to control the movementof the clamp arm 716 from the open and closed positions. In one aspect,the motor 704 b is coupled to a closure gear assembly, which includes aclosure reduction gear set that is supported in meshing engagement withthe closure spur gear. The torque sensor 744 b provides a closure forcefeedback signal to the control circuit 710. The closure force feedbacksignal represents the closure force applied to the clamp arm 716. Theposition sensor 734 may be configured to provide the position of theclosure member as a feedback signal to the control circuit 710.Additional sensors 738 in the end effector 702 may provide the closureforce feedback signal to the control circuit 710. The pivotable clamparm 716 is positioned opposite the ultrasonic blade 718. When ready touse, the control circuit 710 may provide a closure signal to the motorcontrol 708 b. In response to the closure signal, the motor 704 badvances a closure member to grasp tissue between the clamp arm 716 andthe ultrasonic blade 718.

In one aspect, the control circuit 710 is configured to rotate a shaftmember such as the shaft 740 to rotate the end effector 702. The controlcircuit 710 provides a motor set point to a motor control 708 c, whichprovides a drive signal to the motor 704 c. The output shaft of themotor 704 c is coupled to a torque sensor 744 c. The torque sensor 744 cis coupled to a transmission 706 c which is coupled to the shaft 740.The transmission 706 c comprises movable mechanical elements such asrotating elements to control the rotation of the shaft 740 clockwise orcounterclockwise up to and over 360°. In one aspect, the motor 704 c iscoupled to the rotational transmission assembly, which includes a tubegear segment that is formed on (or attached to) the proximal end of theproximal closure tube for operable engagement by a rotational gearassembly that is operably supported on the tool mounting plate. Thetorque sensor 744 c provides a rotation force feedback signal to thecontrol circuit 710. The rotation force feedback signal represents therotation force applied to the shaft 740. The position sensor 734 may beconfigured to provide the position of the closure member as a feedbacksignal to the control circuit 710. Additional sensors 738 such as ashaft encoder may provide the rotational position of the shaft 740 tothe control circuit 710.

In one aspect, the control circuit 710 is configured to articulate theend effector 702. The control circuit 710 provides a motor set point toa motor control 708 d, which provides a drive signal to the motor 704 d.The output shaft of the motor 704 d is coupled to a torque sensor 744 d.The torque sensor 744 d is coupled to a transmission 706 d which iscoupled to an articulation member 742 a. The transmission 706 dcomprises movable mechanical elements such as articulation elements tocontrol the articulation of the end effector 702 ±65°. In one aspect,the motor 704 d is coupled to an articulation nut, which is rotatablyjournaled on the proximal end portion of the distal spine portion and isrotatably driven thereon by an articulation gear assembly. The torquesensor 744 d provides an articulation force feedback signal to thecontrol circuit 710. The articulation force feedback signal representsthe articulation force applied to the end effector 702. Sensors 738,such as an articulation encoder, may provide the articulation positionof the end effector 702 to the control circuit 710.

In another aspect, the articulation function of the robotic surgicalsystem 700 may comprise two articulation members, or links, 742 a, 742b. These articulation members 742 a, 742 b are driven by separate diskson the robot interface (the rack) which are driven by the two motors 708d, 708 e. When the separate firing motor 704 a is provided, each ofarticulation links 742 a, 742 b can be antagonistically driven withrespect to the other link in order to provide a resistive holding motionand a load to the head when it is not moving and to provide anarticulation motion as the head is articulated. The articulation members742 a, 742 b attach to the head at a fixed radius as the head isrotated. Accordingly, the mechanical advantage of the push-and-pull linkchanges as the head is rotated. This change in the mechanical advantagemay be more pronounced with other articulation link drive systems.

In one aspect, the one or more motors 704 a-704 e may comprise a brushedDC motor with a gearbox and mechanical links to a firing member, closuremember, or articulation member. Another example includes electric motors704 a-704 e that operate the movable mechanical elements such as thedisplacement member, articulation links, closure tube, and shaft. Anoutside influence is an unmeasured, unpredictable influence of thingslike tissue, surrounding bodies, and friction on the physical system.Such outside influence can be referred to as drag, which acts inopposition to one of electric motors 704 a-704 e. The outside influence,such as drag, may cause the operation of the physical system to deviatefrom a desired operation of the physical system.

In one aspect, the position sensor 734 may be implemented as an absolutepositioning system. In one aspect, the position sensor 734 may comprisea magnetic rotary absolute positioning system implemented as anAS5055EQFT single-chip magnetic rotary position sensor available fromAustria Microsystems, AG. The position sensor 734 may interface with thecontrol circuit 710 to provide an absolute positioning system. Theposition may include multiple Hall-effect elements located above amagnet and coupled to a CORDIC processor, also known as thedigit-by-digit method and Voider's algorithm, that is provided toimplement a simple and efficient algorithm to calculate hyperbolic andtrigonometric functions that require only addition, subtraction,bitshift, and table lookup operations.

In one aspect, the control circuit 710 may be in communication with oneor more sensors 738. The sensors 738 may be positioned on the endeffector 702 and adapted to operate with the robotic surgical instrument700 to measure the various derived parameters such as the gap distanceversus time, tissue compression versus time, and anvil strain versustime. The sensors 738 may comprise a magnetic sensor, a magnetic fieldsensor, a strain gauge, a load cell, a pressure sensor, a force sensor,a torque sensor, an inductive sensor such as an eddy current sensor, aresistive sensor, a capacitive sensor, an optical sensor, and/or anyother suitable sensor for measuring one or more parameters of the endeffector 702. The sensors 738 may include one or more sensors. Thesensors 738 may be located on the clamp arm 716 to determine tissuelocation using segmented electrodes. The torque sensors 744 a-744 e maybe configured to sense force such as firing force, closure force, and/orarticulation force, among others. Accordingly, the control circuit 710can sense (1) the closure load experienced by the distal closure tubeand its position, (2) the firing member at the rack and its position,(3) what portion of the ultrasonic blade 718 has tissue on it, and (4)the load and position on both articulation rods.

In one aspect, the one or more sensors 738 may comprise a strain gauge,such as a micro-strain gauge, configured to measure the magnitude of thestrain in the clamp arm 716 during a clamped condition. The strain gaugeprovides an electrical signal whose amplitude varies with the magnitudeof the strain. The sensors 738 may comprise a pressure sensor configuredto detect a pressure generated by the presence of compressed tissuebetween the clamp arm 716 and the ultrasonic blade 718. The sensors 738may be configured to detect impedance of a tissue section locatedbetween the clamp arm 716 and the ultrasonic blade 718 that isindicative of the thickness and/or fullness of tissue locatedtherebetween.

In one aspect, the sensors 738 may be implemented as one or more limitswitches, electromechanical devices, solid-state switches, Hall-effectdevices, magneto-resistive (MR) devices, giant magneto-resistive (GMR)devices, magnetometers, among others. In other implementations, thesensors 738 may be implemented as solid-state switches that operateunder the influence of light, such as optical sensors, IR sensors,ultraviolet sensors, among others. Still, the switches may besolid-state devices such as transistors (e.g., FET, junction FET,MOSFET, bipolar, and the like). In other implementations, the sensors738 may include electrical conductorless switches, ultrasonic switches,accelerometers, and inertial sensors, among others.

In one aspect, the sensors 738 may be configured to measure forcesexerted on the clamp arm 716 by the closure drive system. For example,one or more sensors 738 can be at an interaction point between theclosure tube and the clamp arm 716 to detect the closure forces appliedby the closure tube to the clamp arm 716. The forces exerted on theclamp arm 716 can be representative of the tissue compressionexperienced by the tissue section captured between the clamp arm 716 andthe ultrasonic blade 718. The one or more sensors 738 can be positionedat various interaction points along the closure drive system to detectthe closure forces applied to the clamp arm 716 by the closure drivesystem. The one or more sensors 738 may be sampled in real time during aclamping operation by the processor of the control circuit 710. Thecontrol circuit 710 receives real-time sample measurements to provideand analyze time-based information and assess, in real time, closureforces applied to the clamp arm 716.

In one aspect, a current sensor 736 can be employed to measure thecurrent drawn by each of the motors 704 a-704 e. The force required toadvance any of the movable mechanical elements such as the closuremember 714 corresponds to the current drawn by one of the motors 704a-704 e. The force is converted to a digital signal and provided to thecontrol circuit 710. The control circuit 710 can be configured tosimulate the response of the actual system of the instrument in thesoftware of the controller. A displacement member can be actuated tomove the closure member 714 in the end effector 702 at or near a targetvelocity. The robotic surgical instrument 700 can include a feedbackcontroller, which can be one of any feedback controllers, including, butnot limited to a PID, a state feedback, a linear-quadratic (LQR), and/oran adaptive controller, for example. The robotic surgical instrument 700can include a power source to convert the signal from the feedbackcontroller into a physical input such as case voltage, PWM voltage,frequency modulated voltage, current, torque, and/or force, for example.Additional details are disclosed in U.S. patent application Ser. No.15/636,829, titled CLOSED LOOP VELOCITY CONTROL TECHNIQUES FOR ROBOTICSURGICAL INSTRUMENT, filed Jun. 29, 2017, which is herein incorporatedby reference in its entirety.

FIG. 18 illustrates a schematic diagram of a surgical instrument 750configured to control the distal translation of a displacement memberaccording to one aspect of this disclosure. In one aspect, the surgicalinstrument 750 is programmed to control the distal translation of adisplacement member such as the closure member 764. The surgicalinstrument 750 comprises an end effector 752 that may comprise a clamparm 766, a closure member 764, and an ultrasonic blade 768 coupled to anultrasonic transducer 769 driven by an ultrasonic generator 771.

The position, movement, displacement, and/or translation of a lineardisplacement member, such as the closure member 764, can be measured byan absolute positioning system, sensor arrangement, and position sensor784. Because the closure member 764 is coupled to a longitudinallymovable drive member, the position of the closure member 764 can bedetermined by measuring the position of the longitudinally movable drivemember employing the position sensor 784. Accordingly, in the followingdescription, the position, displacement, and/or translation of theclosure member 764 can be achieved by the position sensor 784 asdescribed herein. A control circuit 760 may be programmed to control thetranslation of the displacement member, such as the closure member 764.The control circuit 760, in some examples, may comprise one or moremicrocontrollers, microprocessors, or other suitable processors forexecuting instructions that cause the processor or processors to controlthe displacement member, e.g., the closure member 764, in the mannerdescribed. In one aspect, a timer/counter 781 provides an output signal,such as the elapsed time or a digital count, to the control circuit 760to correlate the position of the closure member 764 as determined by theposition sensor 784 with the output of the timer/counter 781 such thatthe control circuit 760 can determine the position of the closure member764 at a specific time (t) relative to a starting position. Thetimer/counter 781 may be configured to measure elapsed time, countexternal events, or time external events.

The control circuit 760 may generate a motor set point signal 772. Themotor set point signal 772 may be provided to a motor controller 758.The motor controller 758 may comprise one or more circuits configured toprovide a motor drive signal 774 to the motor 754 to drive the motor 754as described herein. In some examples, the motor 754 may be a brushed DCelectric motor. For example, the velocity of the motor 754 may beproportional to the motor drive signal 774. In some examples, the motor754 may be a brushless DC electric motor and the motor drive signal 774may comprise a PWM signal provided to one or more stator windings of themotor 754. Also, in some examples, the motor controller 758 may beomitted, and the control circuit 760 may generate the motor drive signal774 directly.

The motor 754 may receive power from an energy source 762. The energysource 762 may be or include a battery, a super capacitor, or any othersuitable energy source. The motor 754 may be mechanically coupled to theclosure member 764 via a transmission 756. The transmission 756 mayinclude one or more gears or other linkage components to couple themotor 754 to the closure member 764. A position sensor 784 may sense aposition of the closure member 764. The position sensor 784 may be orinclude any type of sensor that is capable of generating position datathat indicate a position of the closure member 764. In some examples,the position sensor 784 may include an encoder configured to provide aseries of pulses to the control circuit 760 as the closure member 764translates distally and proximally. The control circuit 760 may trackthe pulses to determine the position of the closure member 764. Othersuitable position sensors may be used, including, for example, aproximity sensor. Other types of position sensors may provide othersignals indicating motion of the closure member 764. Also, in someexamples, the position sensor 784 may be omitted. Where the motor 754 isa stepper motor, the control circuit 760 may track the position of theclosure member 764 by aggregating the number and direction of steps thatthe motor 754 has been instructed to execute. The position sensor 784may be located in the end effector 752 or at any other portion of theinstrument.

The control circuit 760 may be in communication with one or more sensors788. The sensors 788 may be positioned on the end effector 752 andadapted to operate with the surgical instrument 750 to measure thevarious derived parameters such as gap distance versus time, tissuecompression versus time, and anvil strain versus time. The sensors 788may comprise a magnetic sensor, a magnetic field sensor, a strain gauge,a pressure sensor, a force sensor, an inductive sensor such as an eddycurrent sensor, a resistive sensor, a capacitive sensor, an opticalsensor, and/or any other suitable sensor for measuring one or moreparameters of the end effector 752. The sensors 788 may include one ormore sensors.

The one or more sensors 788 may comprise a strain gauge, such as amicro-strain gauge, configured to measure the magnitude of the strain inthe clamp arm 766 during a clamped condition. The strain gauge providesan electrical signal whose amplitude varies with the magnitude of thestrain. The sensors 788 may comprise a pressure sensor configured todetect a pressure generated by the presence of compressed tissue betweenthe clamp arm 766 and the ultrasonic blade 768. The sensors 788 may beconfigured to detect impedance of a tissue section located between theclamp arm 766 and the ultrasonic blade 768 that is indicative of thethickness and/or fullness of tissue located therebetween.

The sensors 788 may be is configured to measure forces exerted on theclamp arm 766 by a closure drive system. For example, one or moresensors 788 can be at an interaction point between a closure tube andthe clamp arm 766 to detect the closure forces applied by a closure tubeto the clamp arm 766. The forces exerted on the clamp arm 766 can berepresentative of the tissue compression experienced by the tissuesection captured between the clamp arm 766 and the ultrasonic blade 768.The one or more sensors 788 can be positioned at various interactionpoints along the closure drive system to detect the closure forcesapplied to the clamp arm 766 by the closure drive system. The one ormore sensors 788 may be sampled in real time during a clamping operationby a processor of the control circuit 760. The control circuit 760receives real-time sample measurements to provide and analyze time-basedinformation and assess, in real time, closure forces applied to theclamp arm 766.

A current sensor 786 can be employed to measure the current drawn by themotor 754. The force required to advance the closure member 764corresponds to the current drawn by the motor 754. The force isconverted to a digital signal and provided to the control circuit 760.

The control circuit 760 can be configured to simulate the response ofthe actual system of the instrument in the software of the controller. Adisplacement member can be actuated to move a closure member 764 in theend effector 752 at or near a target velocity. The surgical instrument750 can include a feedback controller, which can be one of any feedbackcontrollers, including, but not limited to a PID, a state feedback, LQR,and/or an adaptive controller, for example. The surgical instrument 750can include a power source to convert the signal from the feedbackcontroller into a physical input such as case voltage, PWM voltage,frequency modulated voltage, current, torque, and/or force, for example.

The actual drive system of the surgical instrument 750 is configured todrive the displacement member, cutting member, or closure member 764, bya brushed DC motor with gearbox and mechanical links to an articulationand/or knife system. Another example is the electric motor 754 thatoperates the displacement member and the articulation driver, forexample, of an interchangeable shaft assembly. An outside influence isan unmeasured, unpredictable influence of things like tissue,surrounding bodies and friction on the physical system. Such outsideinfluence can be referred to as drag which acts in opposition to theelectric motor 754. The outside influence, such as drag, may cause theoperation of the physical system to deviate from a desired operation ofthe physical system.

Various example aspects are directed to a surgical instrument 750comprising an end effector 752 with motor-driven surgical sealing andcutting implements. For example, a motor 754 may drive a displacementmember distally and proximally along a longitudinal axis of the endeffector 752. The end effector 752 may comprise a pivotable clamp arm766 and, when configured for use, an ultrasonic blade 768 positionedopposite the clamp arm 766. A clinician may grasp tissue between theclamp arm 766 and the ultrasonic blade 768, as described herein. Whenready to use the instrument 750, the clinician may provide a firingsignal, for example by depressing a trigger of the instrument 750. Inresponse to the firing signal, the motor 754 may drive the displacementmember distally along the longitudinal axis of the end effector 752 froma proximal stroke begin position to a stroke end position distal of thestroke begin position. As the displacement member translates distally,the closure member 764 with a cutting element positioned at a distalend, may cut the tissue between the ultrasonic blade 768 and the clamparm 766.

In various examples, the surgical instrument 750 may comprise a controlcircuit 760 programmed to control the distal translation of thedisplacement member, such as the closure member 764, for example, basedon one or more tissue conditions. The control circuit 760 may beprogrammed to sense tissue conditions, such as thickness, eitherdirectly or indirectly, as described herein. The control circuit 760 maybe programmed to select a control program based on tissue conditions. Acontrol program may describe the distal motion of the displacementmember. Different control programs may be selected to better treatdifferent tissue conditions. For example, when thicker tissue ispresent, the control circuit 760 may be programmed to translate thedisplacement member at a lower velocity and/or with lower power. Whenthinner tissue is present, the control circuit 760 may be programmed totranslate the displacement member at a higher velocity and/or withhigher power.

In some examples, the control circuit 760 may initially operate themotor 754 in an open loop configuration for a first open loop portion ofa stroke of the displacement member. Based on a response of theinstrument 750 during the open loop portion of the stroke, the controlcircuit 760 may select a firing control program. The response of theinstrument may include, a translation distance of the displacementmember during the open loop portion, a time elapsed during the open loopportion, energy provided to the motor 754 during the open loop portion,a sum of pulse widths of a motor drive signal, etc. After the open loopportion, the control circuit 760 may implement the selected firingcontrol program for a second portion of the displacement member stroke.For example, during the closed loop portion of the stroke, the controlcircuit 760 may modulate the motor 754 based on translation datadescribing a position of the displacement member in a closed loop mannerto translate the displacement member at a constant velocity. Additionaldetails are disclosed in U.S. patent application Ser. No. 15/720,852,titled SYSTEM AND METHODS FOR CONTROLLING A DISPLAY OF A SURGICALINSTRUMENT, filed Sep. 29, 2017, which is herein incorporated byreference in its entirety.

FIG. 19 is a schematic diagram of a surgical instrument 790 configuredto control various functions according to one aspect of this disclosure.In one aspect, the surgical instrument 790 is programmed to controldistal translation of a displacement member such as the closure member764. The surgical instrument 790 comprises an end effector 792 that maycomprise a clamp arm 766, a closure member 764, and an ultrasonic blade768 which may be interchanged with or work in conjunction with one ormore RF electrodes 796 (shown in dashed line). The ultrasonic blade 768is coupled to an ultrasonic transducer 769 driven by an ultrasonicgenerator 771.

In one aspect, sensors 788 may be implemented as a limit switch,electromechanical device, solid-state switches, Hall-effect devices, MRdevices, GMR devices, magnetometers, among others. In otherimplementations, the sensors 638 may be solid-state switches thatoperate under the influence of light, such as optical sensors, IRsensors, ultraviolet sensors, among others. Still, the switches may besolid-state devices such as transistors (e.g., FET, junction FET,MOSFET, bipolar, and the like). In other implementations, the sensors788 may include electrical conductorless switches, ultrasonic switches,accelerometers, and inertial sensors, among others.

In one aspect, the position sensor 784 may be implemented as an absolutepositioning system comprising a magnetic rotary absolute positioningsystem implemented as an AS5055EQFT single-chip magnetic rotary positionsensor available from Austria Microsystems, AG. The position sensor 784may interface with the control circuit 760 to provide an absolutepositioning system. The position may include multiple Hall-effectelements located above a magnet and coupled to a CORDIC processor, alsoknown as the digit-by-digit method and Volder's algorithm, that isprovided to implement a simple and efficient algorithm to calculatehyperbolic and trigonometric functions that require only addition,subtraction, bitshift, and table lookup operations.

In some examples, the position sensor 784 may be omitted. Where themotor 754 is a stepper motor, the control circuit 760 may track theposition of the closure member 764 by aggregating the number anddirection of steps that the motor has been instructed to execute. Theposition sensor 784 may be located in the end effector 792 or at anyother portion of the instrument.

The control circuit 760 may be in communication with one or more sensors788. The sensors 788 may be positioned on the end effector 792 andadapted to operate with the surgical instrument 790 to measure thevarious derived parameters such as gap distance versus time, tissuecompression versus time, and anvil strain versus time. The sensors 788may comprise a magnetic sensor, a magnetic field sensor, a strain gauge,a pressure sensor, a force sensor, an inductive sensor such as an eddycurrent sensor, a resistive sensor, a capacitive sensor, an opticalsensor, and/or any other suitable sensor for measuring one or moreparameters of the end effector 792. The sensors 788 may include one ormore sensors.

An RF energy source 794 is coupled to the end effector 792 and isapplied to the RF electrode 796 when the RF electrode 796 is provided inthe end effector 792 in place of the ultrasonic blade 768 or to work inconjunction with the ultrasonic blade 768. For example, the ultrasonicblade is made of electrically conductive metal and may be employed asthe return path for electrosurgical RF current. The control circuit 760controls the delivery of the RF energy to the RF electrode 796.

Additional details are disclosed in U.S. Patent application Ser. No.15/636,096, titled SURGICAL SYSTEM COUPLABLE WITH STAPLE CARTRIDGE ANDRADIO FREQUENCY CARTRIDGE, AND METHOD OF USING SAME, filed Jun. 28,2017, which is herein incorporated by reference in its entirety.

Adaptive Ultrasonic Blade Control Algorithms

In various aspects smart ultrasonic energy devices may comprise adaptivealgorithms to control the operation of the ultrasonic blade. In oneaspect, the ultrasonic blade adaptive control algorithms are configuredto identify tissue type and adjust device parameters. In one aspect, theultrasonic blade control algorithms are configured to parameterizetissue type. An algorithm to detect the collagen/elastic ratio of tissueto tune the amplitude of the distal tip of the ultrasonic blade isdescribed in the following section of the present disclosure. Variousaspects of smart ultrasonic energy devices are described herein inconnection with FIGS. 1-94 , for example. Accordingly, the followingdescription of adaptive ultrasonic blade control algorithms should beread in conjunction with FIGS. 1-94 and the description associatedtherewith.

Tissue Type Identification And Device Parameter Adjustments

In certain surgical procedures it would be desirable to employ adaptiveultrasonic blade control algorithms. In one aspect, adaptive ultrasonicblade control algorithms may be employed to adjust the parameters of theultrasonic device based on the type of tissue in contact with theultrasonic blade. In one aspect, the parameters of the ultrasonic devicemay be adjusted based on the location of the tissue within the jaws ofthe ultrasonic end effector, for example, the location of the tissuebetween the clamp arm and the ultrasonic blade. The impedance of theultrasonic transducer may be employed to differentiate what percentageof the tissue is located in the distal or proximal end of the endeffector. The reactions of the ultrasonic device may be based on thetissue type or compressibility of the tissue. In another aspect, theparameters of the ultrasonic device may be adjusted based on theidentified tissue type or parameterization. For example, the mechanicaldisplacement amplitude of the distal tip of the ultrasonic blade may betuned based on the ration of collagen to elastin tissue detected duringthe tissue identification procedure. The ratio of collagen to elastintissue may be detected used a variety of techniques including infrared(IR) surface reflectance and emissivity. The force applied to the tissueby the clamp arm and/or the stroke of the clamp arm to produce gap andcompression. Electrical continuity across a jaw equipped with electrodesmay be employed to determine what percentage of the jaw is covered withtissue.

FIG. 20 is a system 800 configured to execute adaptive ultrasonic bladecontrol algorithms in a surgical data network comprising a modularcommunication hub, in accordance with at least one aspect of the presentdisclosure. In one aspect, the generator module 240 is configured toexecute the adaptive ultrasonic blade control algorithm(s) 802 asdescribed herein with reference to FIGS. 53-94 . In another aspect, thedevice/instrument 235 is configured to execute the adaptive ultrasonicblade control algorithm(s) 804 as described herein with reference toFIGS. 53-94 . In another aspect, both the device/instrument 235 and thedevice/instrument 235 are configured to execute the adaptive ultrasonicblade control algorithms 802, 804 as described herein with reference toFIGS. 53-94 .

The generator module 240 may comprise a patient isolated stage incommunication with a non-isolated stage via a power transformer. Asecondary winding of the power transformer is contained in the isolatedstage and may comprise a tapped configuration (e.g., a center-tapped ora non-center-tapped configuration) to define drive signal outputs fordelivering drive signals to different surgical instruments, such as, forexample, an ultrasonic surgical instrument, an RF electrosurgicalinstrument, and a multifunction surgical instrument which includesultrasonic and RF energy modes that can be delivered alone orsimultaneously. In particular, the drive signal outputs may output anultrasonic drive signal (e.g., a 420V root-mean-square (RMS) drivesignal) to an ultrasonic surgical instrument 241, and the drive signaloutputs may output an RF electrosurgical drive signal (e.g., a 100V RMSdrive signal) to an RF electrosurgical instrument 241. Aspects of thegenerator module 240 are described herein with reference to FIGS.21-28B.

The generator module 240 or the device/instrument 235 or both arecoupled to the modular control tower 236 connected to multiple operatingtheater devices such as, for example, intelligent surgical instruments,robots, and other computerized devices located in the operating theater,as described with reference to FIGS. 8-11 , for example.

FIG. 21 illustrates an example of a generator 900, which is one form ofa generator configured to couple to an ultrasonic instrument and furtherconfigured to execute adaptive ultrasonic blade control algorithms in asurgical data network comprising a modular communication hub as shown inFIG. 20 . The generator 900 is configured to deliver multiple energymodalities to a surgical instrument. The generator 900 provides RF andultrasonic signals for delivering energy to a surgical instrument eitherindependently or simultaneously. The RF and ultrasonic signals may beprovided alone or in combination and may be provided simultaneously. Asnoted above, at least one generator output can deliver multiple energymodalities (e.g., ultrasonic, bipolar or monopolar RF, irreversibleand/or reversible electroporation, and/or microwave energy, amongothers) through a single port, and these signals can be deliveredseparately or simultaneously to the end effector to treat tissue. Thegenerator 900 comprises a processor 902 coupled to a waveform generator904. The processor 902 and waveform generator 904 are configured togenerate a variety of signal waveforms based on information stored in amemory coupled to the processor 902, not shown for clarity ofdisclosure. The digital information associated with a waveform isprovided to the waveform generator 904 which includes one or more DACcircuits to convert the digital input into an analog output. The analogoutput is fed to an amplifier 1106 for signal conditioning andamplification. The conditioned and amplified output of the amplifier 906is coupled to a power transformer 908. The signals are coupled acrossthe power transformer 908 to the secondary side, which is in the patientisolation side. A first signal of a first energy modality is provided tothe surgical instrument between the terminals labeled ENERGY₁ andRETURN. A second signal of a second energy modality is coupled across acapacitor 910 and is provided to the surgical instrument between theterminals labeled ENERGY₂ and RETURN. It will be appreciated that morethan two energy modalities may be output and thus the subscript “n” maybe used to designate that up to n ENERGY_(n) terminals may be provided,where n is a positive integer greater than 1. It also will beappreciated that up to “n” return paths RETURN_(n) may be providedwithout departing from the scope of the present disclosure.

A first voltage sensing circuit 912 is coupled across the terminalslabeled ENERGY₁ and the RETURN path to measure the output voltagetherebetween. A second voltage sensing circuit 924 is coupled across theterminals labeled ENERGY₂ and the RETURN path to measure the outputvoltage therebetween. A current sensing circuit 914 is disposed inseries with the RETURN leg of the secondary side of the powertransformer 908 as shown to measure the output current for either energymodality. If different return paths are provided for each energymodality, then a separate current sensing circuit should be provided ineach return leg. The outputs of the first and second voltage sensingcircuits 912, 924 are provided to respective isolation transformers 916,922 and the output of the current sensing circuit 914 is provided toanother isolation transformer 918. The outputs of the isolationtransformers 916, 928, 922 in the on the primary side of the powertransformer 908 (non-patient isolated side) are provided to a one ormore ADC circuit 926. The digitized output of the ADC circuit 926 isprovided to the processor 902 for further processing and computation.The output voltages and output current feedback information can beemployed to adjust the output voltage and current provided to thesurgical instrument and to compute output impedance, among otherparameters. Input/output communications between the processor 902 andpatient isolated circuits is provided through an interface circuit 920.Sensors also may be in electrical communication with the processor 902by way of the interface circuit 920.

In one aspect, the impedance may be determined by the processor 902 bydividing the output of either the first voltage sensing circuit 912coupled across the terminals labeled ENERGY₁/RETURN or the secondvoltage sensing circuit 924 coupled across the terminals labeledENERGY₂/RETURN by the output of the current sensing circuit 914 disposedin series with the RETURN leg of the secondary side of the powertransformer 908. The outputs of the first and second voltage sensingcircuits 912, 924 are provided to separate isolations transformers 916,922 and the output of the current sensing circuit 914 is provided toanother isolation transformer 916. The digitized voltage and currentsensing measurements from the ADC circuit 926 are provided the processor902 for computing impedance. As an example, the first energy modalityENERGY₁ may be ultrasonic energy and the second energy modality ENERGY₂may be RF energy. Nevertheless, in addition to ultrasonic and bipolar ormonopolar RF energy modalities, other energy modalities includeirreversible and/or reversible electroporation and/or microwave energy,among others. Also, although the example illustrated in FIG. 21 shows asingle return path RETURN may be provided for two or more energymodalities, in other aspects, multiple return paths RETURN_(n) may beprovided for each energy modality ENERGY_(n). Thus, as described herein,the ultrasonic transducer impedance may be measured by dividing theoutput of the first voltage sensing circuit 912 by the current sensingcircuit 914 and the tissue impedance may be measured by dividing theoutput of the second voltage sensing circuit 924 by the current sensingcircuit 914.

As shown in FIG. 21 , the generator 900 comprising at least one outputport can include a power transformer 908 with a single output and withmultiple taps to provide power in the form of one or more energymodalities, such as ultrasonic, bipolar or monopolar RF, irreversibleand/or reversible electroporation, and/or microwave energy, amongothers, for example, to the end effector depending on the type oftreatment of tissue being performed. For example, the generator 900 candeliver energy with higher voltage and lower current to drive anultrasonic transducer, with lower voltage and higher current to drive RFelectrodes for sealing tissue, or with a coagulation waveform for spotcoagulation using either monopolar or bipolar RF electrosurgicalelectrodes. The output waveform from the generator 900 can be steered,switched, or filtered to provide the frequency to the end effector ofthe surgical instrument. The connection of an ultrasonic transducer tothe generator 900 output would be preferably located between the outputlabeled ENERGY₁ and RETURN as shown in FIG. 21 . In one example, aconnection of RF bipolar electrodes to the generator 900 output would bepreferably located between the output labeled ENERGY₂ and RETURN. In thecase of monopolar output, the preferred connections would be activeelectrode (e.g., pencil or other probe) to the ENERGY₂ output and asuitable return pad connected to the RETURN output.

Additional details are disclosed in U.S. Patent Application PublicationNo. 2017/0086914, titled TECHNIQUES FOR OPERATING GENERATOR FORDIGITALLY GENERATING ELECTRICAL SIGNAL WAVEFORMS AND SURGICALINSTRUMENTS, which published on Mar. 30, 2017, which is hereinincorporated by reference in its entirety.

As used throughout this description, the term “wireless” and itsderivatives may be used to describe circuits, devices, systems, methods,techniques, communications channels, etc., that may communicate datathrough the use of modulated electromagnetic radiation through anon-solid medium. The term does not imply that the associated devices donot contain any wires, although in some aspects they might not. Thecommunication module may implement any of a number of wireless or wiredcommunication standards or protocols, including but not limited to Wi-Fi(IEEE 802.11 family), WiMAX (IEEE 802.16 family), IEEE 802.20, long termevolution (LTE), Ev-DO, HSPA+, HSDPA+, HSUPA+, EDGE, GSM, GPRS, CDMA,TDMA, DECT, Bluetooth, Ethernet derivatives thereof, as well as anyother wireless and wired protocols that are designated as 3G, 4G, 5G,and beyond. The computing module may include a plurality ofcommunication modules. For instance, a first communication module may bededicated to shorter range wireless communications such as Wi-Fi andBluetooth and a second communication module may be dedicated to longerrange wireless communications such as GPS, EDGE, GPRS, CDMA, WiMAX, LTE,Ev-DO, and others.

As used herein a processor or processing unit is an electronic circuitwhich performs operations on some external data source, usually memoryor some other data stream. The term is used herein to refer to thecentral processor (central processing unit) in a system or computersystems (especially systems on a chip (SoCs)) that combine a number ofspecialized “processors.”

As used herein, a system on a chip or system on chip (SoC or SOC) is anintegrated circuit (also known as an “IC” or “chip”) that integrates allcomponents of a computer or other electronic systems. It may containdigital, analog, mixed-signal, and often radio-frequency functions-allon a single substrate. A SoC integrates a microcontroller (ormicroprocessor) with advanced peripherals like graphics processing unit(GPU), Wi-Fi module, or coprocessor. A SoC may or may not containbuilt-in memory.

As used herein, a microcontroller or controller is a system thatintegrates a microprocessor with peripheral circuits and memory. Amicrocontroller (or MCU for microcontroller unit) may be implemented asa small computer on a single integrated circuit. It may be similar to aSoC; an SoC may include a microcontroller as one of its components. Amicrocontroller may contain one or more core processing units (CPUs)along with memory and programmable input/output peripherals. Programmemory in the form of Ferroelectric RAM, NOR flash or OTP ROM is alsooften included on chip, as well as a small amount of RAM.Microcontrollers may be employed for embedded applications, in contrastto the microprocessors used in personal computers or other generalpurpose applications consisting of various discrete chips.

As used herein, the term controller or microcontroller may be astand-alone IC or chip device that interfaces with a peripheral device.This may be a link between two parts of a computer or a controller on anexternal device that manages the operation of (and connection with) thatdevice.

Any of the processors or microcontrollers described herein, may beimplemented by any single core or multicore processor such as thoseknown under the trade name ARM Cortex by Texas Instruments. In oneaspect, the processor may be an LM4F230H5QR ARM Cortex-M4F ProcessorCore, available from Texas Instruments, for example, comprising on-chipmemory of 256 KB single-cycle flash memory, or other non-volatilememory, up to 40 MHz, a prefetch buffer to improve performance above 40MHz, a 32 KB single-cycle serial random access memory (SRAM), internalread-only memory (ROM) loaded with StellarisWare® software, 2 KBelectrically erasable programmable read-only memory (EEPROM), one ormore pulse width modulation (PWM) modules, one or more quadratureencoder inputs (QEI) analog, one or more 12-bit Analog-to-DigitalConverters (ADC) with 12 analog input channels, details of which areavailable for the product datasheet.

In one aspect, the processor may comprise a safety controller comprisingtwo controller-based families such as TMS570 and RM4x known under thetrade name Hercules ARM Cortex R4, also by Texas Instruments. The safetycontroller may be configured specifically for IEC 61508 and ISO 26262safety critical applications, among others, to provide advancedintegrated safety features while delivering scalable performance,connectivity, and memory options.

Modular devices include the modules (as described in connection withFIGS. 3 and 9 , for example) that are receivable within a surgical huband the surgical devices or instruments that can be connected to thevarious modules in order to connect or pair with the correspondingsurgical hub. The modular devices include, for example, intelligentsurgical instruments, medical imaging devices, suction/irrigationdevices, smoke evacuators, energy generators, ventilators, insufflators,and displays. The modular devices described herein can be controlled bycontrol algorithms. The control algorithms can be executed on themodular device itself, on the surgical hub to which the particularmodular device is paired, or on both the modular device and the surgicalhub (e.g., via a distributed computing architecture). In someexemplifications, the modular devices' control algorithms control thedevices based on data sensed by the modular device itself (i.e., bysensors in, on, or connected to the modular device). This data can berelated to the patient being operated on (e.g., tissue properties orinsufflation pressure) or the modular device itself (e.g., the rate atwhich a knife is being advanced, motor current, or energy levels). Forexample, a control algorithm for a surgical stapling and cuttinginstrument can control the rate at which the instrument's motor drivesits knife through tissue according to resistance encountered by theknife as it advances.

FIG. 22 illustrates one form of a surgical system 1000 comprising agenerator 1100 and various surgical instruments 1104, 1106, 1108 usabletherewith, where the surgical instrument 1104 is an ultrasonic surgicalinstrument, the surgical instrument 1106 is an RF electrosurgicalinstrument, and the multifunction surgical instrument 1108 is acombination ultrasonic/RF electrosurgical instrument. The generator 1100is configurable for use with a variety of surgical instruments.According to various forms, the generator 1100 may be configurable foruse with different surgical instruments of different types including,for example, ultrasonic surgical instruments 1104, RF electrosurgicalinstruments 1106, and multifunction surgical instruments 1108 thatintegrate RF and ultrasonic energies delivered simultaneously from thegenerator 1100. Although in the form of FIG. 22 the generator 1100 isshown separate from the surgical instruments 1104, 1106, 1108 in oneform, the generator 1100 may be formed integrally with any of thesurgical instruments 1104, 1106, 1108 to form a unitary surgical system.The generator 1100 comprises an input device 1110 located on a frontpanel of the generator 1100 console. The input device 1110 may compriseany suitable device that generates signals suitable for programming theoperation of the generator 1100. The generator 1100 may be configuredfor wired or wireless communication.

The generator 1100 is configured to drive multiple surgical instruments1104, 1106, 1108. The first surgical instrument is an ultrasonicsurgical instrument 1104 and comprises a handpiece 1105 (HP), anultrasonic transducer 1120, a shaft 1126, and an end effector 1122. Theend effector 1122 comprises an ultrasonic blade 1128 acousticallycoupled to the ultrasonic transducer 1120 and a clamp arm 1140. Thehandpiece 1105 comprises a trigger 1143 to operate the clamp arm 1140and a combination of the toggle buttons 1134 a, 1134 b, 1134 c toenergize and drive the ultrasonic blade 1128 or other function. Thetoggle buttons 1134 a, 1134 b, 1134 c can be configured to energize theultrasonic transducer 1120 with the generator 1100.

The generator 1100 also is configured to drive a second surgicalinstrument 1106. The second surgical instrument 1106 is an RFelectrosurgical instrument and comprises a handpiece 1107 (HP), a shaft1127, and an end effector 1124. The end effector 1124 compriseselectrodes in clamp arms 1142 a, 1142 b and return through an electricalconductor portion of the shaft 1127. The electrodes are coupled to andenergized by a bipolar energy source within the generator 1100. Thehandpiece 1107 comprises a trigger 1145 to operate the clamp arms 1142a, 1142 b and an energy button 1135 to actuate an energy switch toenergize the electrodes in the end effector 1124.

The generator 1100 also is configured to drive a multifunction surgicalinstrument 1108. The multifunction surgical instrument 1108 comprises ahandpiece 1109 (HP), a shaft 1129, and an end effector 1125. The endeffector 1125 comprises an ultrasonic blade 1149 and a clamp arm 1146.The ultrasonic blade 1149 is acoustically coupled to the ultrasonictransducer 1120. The handpiece 1109 comprises a trigger 1147 to operatethe clamp arm 1146 and a combination of the toggle buttons 1137 a, 1137b, 1137 c to energize and drive the ultrasonic blade 1149 or otherfunction. The toggle buttons 1137 a, 1137 b, 1137 c can be configured toenergize the ultrasonic transducer 1120 with the generator 1100 andenergize the ultrasonic blade 1149 with a bipolar energy source alsocontained within the generator 1100.

The generator 1100 is configurable for use with a variety of surgicalinstruments. According to various forms, the generator 1100 may beconfigurable for use with different surgical instruments of differenttypes including, for example, the ultrasonic surgical instrument 1104,the RF electrosurgical instrument 1106, and the multifunction surgicalinstrument 1108 that integrates RF and ultrasonic energies deliveredsimultaneously from the generator 1100. Although in the form of FIG. 22the generator 1100 is shown separate from the surgical instruments 1104,1106, 1108, in another form the generator 1100 may be formed integrallywith any one of the surgical instruments 1104, 1106, 1108 to form aunitary surgical system. As discussed above, the generator 1100comprises an input device 1110 located on a front panel of the generator1100 console. The input device 1110 may comprise any suitable devicethat generates signals suitable for programming the operation of thegenerator 1100. The generator 1100 also may comprise one or more outputdevices 1112. Further aspects of generators for digitally generatingelectrical signal waveforms and surgical instruments are described in USpatent publication US-2017-0086914-A1, which is herein incorporated byreference in its entirety.

FIG. 23 is an end effector 1122 of the example ultrasonic device 1104,in accordance with at least one aspect of the present disclosure. Theend effector 1122 may comprise a blade 1128 that may be coupled to theultrasonic transducer 1120 via a wave guide. When driven by theultrasonic transducer 1120, the blade 1128 may vibrate and, when broughtinto contact with tissue, may cut and/or coagulate the tissue, asdescribed herein. According to various aspects, and as illustrated inFIG. 23 , the end effector 1122 may also comprise a clamp arm 1140 thatmay be configured for cooperative action with the blade 1128 of the endeffector 1122. With the blade 1128, the clamp arm 1140 may comprise aset of jaws. The clamp arm 1140 may be pivotally connected at a distalend of a shaft 1126 of the instrument portion 1104. The clamp arm 1140may include a clamp arm tissue pad 1163, which may be formed fromTEFLON® or other suitable low-friction material. The pad 1163 may bemounted for cooperation with the blade 1128, with pivotal movement ofthe clamp arm 1140 positioning the clamp pad 1163 in substantiallyparallel relationship to, and in contact with, the blade 1128. By thisconstruction, a tissue bite to be clamped may be grasped between thetissue pad 1163 and the blade 1128. The tissue pad 1163 may be providedwith a sawtooth-like configuration including a plurality of axiallyspaced, proximally extending gripping teeth 1161 to enhance the grippingof tissue in cooperation with the blade 1128. The clamp arm 1140 maytransition from the open position shown in FIG. 23 to a closed position(with the clamp arm 1140 in contact with or proximity to the blade 1128)in any suitable manner. For example, the handpiece 1105 may comprise ajaw closure trigger. When actuated by a clinician, the jaw closuretrigger may pivot the clamp arm 1140 in any suitable manner.

The generator 1100 may be activated to provide the drive signal to theultrasonic transducer 1120 in any suitable manner. For example, thegenerator 1100 may comprise a foot switch 1430 (FIG. 24 ) coupled to thegenerator 1100 via a footswitch cable 1432. A clinician may activate theultrasonic transducer 1120, and thereby the ultrasonic transducer 1120and blade 1128, by depressing the foot switch 1430. In addition, orinstead of the foot switch 1430, some aspects of the device 1104 mayutilize one or more switches positioned on the handpiece 1105 that, whenactivated, may cause the generator 1100 to activate the ultrasonictransducer 1120. In one aspect, for example, the one or more switchesmay comprise a pair of toggle buttons 1134 a, 1134 b, 1134 c (FIG. 22 ),for example, to determine an operating mode of the device 1104. When thetoggle button 1134 a is depressed, for example, the ultrasonic generator1100 may provide a maximum drive signal to the ultrasonic transducer1120, causing it to produce maximum ultrasonic energy output. Depressingtoggle button 1134 b may cause the ultrasonic generator 1100 to providea user-selectable drive signal to the ultrasonic transducer 1120,causing it to produce less than the maximum ultrasonic energy output.The device 1104 additionally or alternatively may comprise a secondswitch to, for example, indicate a position of a jaw closure trigger foroperating the jaws via the clamp arm 1140 of the end effector 1122.Also, in some aspects, the ultrasonic generator 1100 may be activatedbased on the position of the jaw closure trigger, (e.g., as theclinician depresses the jaw closure trigger to close the jaws via theclamp arm 1140, ultrasonic energy may be applied).

Additionally or alternatively, the one or more switches may comprise atoggle button 1134 c that, when depressed, causes the generator 1100 toprovide a pulsed output (FIG. 22 ). The pulses may be provided at anysuitable frequency and grouping, for example. In certain aspects, thepower level of the pulses may be the power levels associated with togglebuttons 1134 a, 1134 b (maximum, less than maximum), for example.

It will be appreciated that a device 1104 may comprise any combinationof the toggle buttons 1134 a, 1134 b, 1134 c (FIG. 22 ). For example,the device 1104 could be configured to have only two toggle buttons: atoggle button 1134 a for producing maximum ultrasonic energy output anda toggle button 1134 c for producing a pulsed output at either themaximum or less than maximum power level per. In this way, the drivesignal output configuration of the generator 1100 could be fivecontinuous signals, or any discrete number of individual pulsed signals(1, 2, 3, 4, or 5). In certain aspects, the specific drive signalconfiguration may be controlled based upon, for example, EEPROM settingsin the generator 1100 and/or user power level selection(s).

In certain aspects, a two-position switch may be provided as analternative to a toggle button 1134 c (FIG. 22 ). For example, a device1104 may include a toggle button 1134 a for producing a continuousoutput at a maximum power level and a two-position toggle button 1134 b.In a first detented position, toggle button 1134 b may produce acontinuous output at a less than maximum power level, and in a seconddetented position the toggle button 1134 b may produce a pulsed output(e.g., at either a maximum or less than maximum power level, dependingupon the EEPROM settings).

In some aspects, the RF electrosurgical end effector 1124, 1125 (FIG. 22) may also comprise a pair of electrodes. The electrodes may be incommunication with the generator 1100, for example, via a cable. Theelectrodes may be used, for example, to measure an impedance of a tissuebite present between the clamp arm 1142 a, 1146 and the blade 1142 b,1149. The generator 1100 may provide a signal (e.g., a non-therapeuticsignal) to the electrodes. The impedance of the tissue bite may befound, for example, by monitoring the current, voltage, etc. of thesignal.

In various aspects, the generator 1100 may comprise several separatefunctional elements, such as modules and/or blocks, as shown in FIG. 24, a diagram of the surgical system 1000 of FIG. 22 . Differentfunctional elements or modules may be configured for driving thedifferent kinds of surgical devices 1104, 1106, 1108. For example anultrasonic generator module may drive an ultrasonic device, such as theultrasonic device 1104. An electrosurgery/RF generator module may drivethe electrosurgical device 1106. The modules may generate respectivedrive signals for driving the surgical devices 1104, 1106, 1108. Invarious aspects, the ultrasonic generator module and/or theelectrosurgery/RF generator module each may be formed integrally withthe generator 1100. Alternatively, one or more of the modules may beprovided as a separate circuit module electrically coupled to thegenerator 1100. (The modules are shown in phantom to illustrate thisoption.) Also, in some aspects, the electrosurgery/RF generator modulemay be formed integrally with the ultrasonic generator module, or viceversa.

In accordance with the described aspects, the ultrasonic generatormodule may produce a drive signal or signals of particular voltages,currents, and frequencies (e.g. 55,500 cycles per second, or Hz). Thedrive signal or signals may be provided to the ultrasonic device 1104,and specifically to the transducer 1120, which may operate, for example,as described above. In one aspect, the generator 1100 may be configuredto produce a drive signal of a particular voltage, current, and/orfrequency output signal that can be stepped with high resolution,accuracy, and repeatability.

In accordance with the described aspects, the electrosurgery/RFgenerator module may generate a drive signal or signals with outputpower sufficient to perform bipolar electrosurgery using radio frequency(RF) energy. In bipolar electrosurgery applications, the drive signalmay be provided, for example, to the electrodes of the electrosurgicaldevice 1106, for example, as described above. Accordingly, the generator1100 may be configured for therapeutic purposes by applying electricalenergy to the tissue sufficient for treating the tissue (e.g.,coagulation, cauterization, tissue welding, etc.).

The generator 1100 may comprise an input device 2150 (FIG. 27B) located,for example, on a front panel of the generator 1100 console. The inputdevice 2150 may comprise any suitable device that generates signalssuitable for programming the operation of the generator 1100. Inoperation, the user can program or otherwise control operation of thegenerator 1100 using the input device 2150. The input device 2150 maycomprise any suitable device that generates signals that can be used bythe generator (e.g., by one or more processors contained in thegenerator) to control the operation of the generator 1100 (e.g.,operation of the ultrasonic generator module and/or electrosurgery/RFgenerator module). In various aspects, the input device 2150 includesone or more of: buttons, switches, thumbwheels, keyboard, keypad, touchscreen monitor, pointing device, remote connection to a general purposeor dedicated computer. In other aspects, the input device 2150 maycomprise a suitable user interface, such as one or more user interfacescreens displayed on a touch screen monitor, for example. Accordingly,by way of the input device 2150, the user can set or program variousoperating parameters of the generator, such as, for example, current(I), voltage (V), frequency (f), and/or period (T) of a drive signal orsignals generated by the ultrasonic generator module and/orelectrosurgery/RF generator module.

The generator 1100 may also comprise an output device 2140 (FIG. 27B)located, for example, on a front panel of the generator 1100 console.The output device 2140 includes one or more devices for providing asensory feedback to a user. Such devices may comprise, for example,visual feedback devices (e.g., an LCD display screen, LED indicators),audio feedback devices (e.g., a speaker, a buzzer) or tactile feedbackdevices (e.g., haptic actuators).

Although certain modules and/or blocks of the generator 1100 may bedescribed by way of example, it can be appreciated that a greater orlesser number of modules and/or blocks may be used and still fall withinthe scope of the aspects. Further, although various aspects may bedescribed in terms of modules and/or blocks to facilitate description,such modules and/or blocks may be implemented by one or more hardwarecomponents, e.g., processors, Digital Signal Processors (DSPs),Programmable Logic Devices (PLDs), Application Specific IntegratedCircuits (ASICs), circuits, registers and/or software components, e.g.,programs, subroutines, logic and/or combinations of hardware andsoftware components.

In one aspect, the ultrasonic generator drive module andelectrosurgery/RF drive module 1110 (FIG. 22 ) may comprise one or moreembedded applications implemented as firmware, software, hardware, orany combination thereof. The modules may comprise various executablemodules such as software, programs, data, drivers, application programinterfaces (APIs), and so forth. The firmware may be stored innonvolatile memory (NVM), such as in bit-masked read-only memory (ROM)or flash memory. In various implementations, storing the firmware in ROMmay preserve flash memory. The NVM may comprise other types of memoryincluding, for example, programmable ROM (PROM), erasable programmableROM (EPROM), electrically erasable programmable ROM (EEPROM), or batterybacked random-access memory (RAM) such as dynamic RAM (DRAM),Double-Data-Rate DRAM (DDRAM), and/or synchronous DRAM (SDRAM).

In one aspect, the modules comprise a hardware component implemented asa processor for executing program instructions for monitoring variousmeasurable characteristics of the devices 1104, 1106, 1108 andgenerating a corresponding output drive signal or signals for operatingthe devices 1104, 1106, 1108. In aspects in which the generator 1100 isused in conjunction with the device 1104, the drive signal may drive theultrasonic transducer 1120 in cutting and/or coagulation operatingmodes. Electrical characteristics of the device 1104 and/or tissue maybe measured and used to control operational aspects of the generator1100 and/or provided as feedback to the user. In aspects in which thegenerator 1100 is used in conjunction with the device 1106, the drivesignal may supply electrical energy (e.g., RF energy) to the endeffector 1124 in cutting, coagulation and/or desiccation modes.Electrical characteristics of the device 1106 and/or tissue may bemeasured and used to control operational aspects of the generator 1100and/or provided as feedback to the user. In various aspects, aspreviously discussed, the hardware components may be implemented as DSP,PLD, ASIC, circuits, and/or registers. In one aspect, the processor maybe configured to store and execute computer software programinstructions to generate the step function output signals for drivingvarious components of the devices 1104, 1106, 1108, such as theultrasonic transducer 1120 and the end effectors 1122, 1124, 1125.

An electromechanical ultrasonic system includes an ultrasonictransducer, a waveguide, and an ultrasonic blade. The electromechanicalultrasonic system has an initial resonant frequency defined by thephysical properties of the ultrasonic transducer, the waveguide, and theultrasonic blade. The ultrasonic transducer is excited by an alternatingvoltage V_(g)(t) and current I_(g)(t) signal equal to the resonantfrequency of the electromechanical ultrasonic system. When theelectromechanical ultrasonic system is at resonance, the phasedifference between the voltage V_(g)(t) and current I_(g)(t) signals iszero. Stated another way, at resonance the inductive impedance is equalto the capacitive impedance. As the ultrasonic blade heats up, thecompliance of the ultrasonic blade (modeled as an equivalentcapacitance) causes the resonant frequency of the electromechanicalultrasonic system to shift. Thus, the inductive impedance is no longerequal to the capacitive impedance causing a mismatch between the drivefrequency and the resonant frequency of the electromechanical ultrasonicsystem. The system is now operating “off-resonance.” The mismatchbetween the drive frequency and the resonant frequency is manifested asa phase difference between the voltage V_(g)(t) and current I_(g)(t)signals applied to the ultrasonic transducer. The generator electronicscan easily monitor the phase difference between the voltage V_(g)(t) andcurrent I_(g)(t) signals and can continuously adjust the drive frequencyuntil the phase difference is once again zero. At this point, the newdrive frequency is equal to the new resonant frequency of theelectromechanical ultrasonic system. The change in phase and/orfrequency can be used as an indirect measurement of the ultrasonic bladetemperature.

As shown in FIG. 25 , the electromechanical properties of the ultrasonictransducer may be modeled as an equivalent circuit comprising a firstbranch having a static capacitance and a second “motional” branch havinga serially connected inductance, resistance and capacitance that definethe electromechanical properties of a resonator. Known ultrasonicgenerators may include a tuning inductor for tuning out the staticcapacitance at a resonant frequency so that substantially all ofgenerator's drive signal current flows into the motional branch.Accordingly, by using a tuning inductor, the generator's drive signalcurrent represents the motional branch current, and the generator isthus able to control its drive signal to maintain the ultrasonictransducer's resonant frequency. The tuning inductor may also transformthe phase impedance plot of the ultrasonic transducer to improve thegenerator's frequency lock capabilities. However, the tuning inductormust be matched with the specific static capacitance of an ultrasonictransducer at the operational resonance frequency. In other words, adifferent ultrasonic transducer having a different static capacitancerequires a different tuning inductor.

FIG. 25 illustrates an equivalent circuit 1500 of a ultrasonictransducer, such as the ultrasonic transducer 1120, according to oneaspect. The circuit 1500 comprises a first “motional” branch having aserially connected inductance L_(s), resistance R_(s) and capacitanceC_(s) that define the electromechanical properties of the resonator, anda second capacitive branch having a static capacitance C₀. Drive currentI_(g)(t) may be received from a generator at a drive voltage V_(g)(t),with motional current I_(m)(t) flowing through the first branch andcurrent I_(g)(t)-I_(m)(t) flowing through the capacitive branch. Controlof the electromechanical properties of the ultrasonic transducer may beachieved by suitably controlling I_(g)(t) and V_(g)(t). As explainedabove, known generator architectures may include a tuning inductor L_(t)(shown in phantom in FIG. 25 ) in a parallel resonance circuit fortuning out the static capacitance C₀ at a resonant frequency so thatsubstantially all of the generator's current output I_(g)(t) flowsthrough the motional branch. In this way, control of the motional branchcurrent I_(m)(t) is achieved by controlling the generator current outputI_(g)(t). The tuning inductor L_(t) is specific to the staticcapacitance C₀ of an ultrasonic transducer, however, and a differentultrasonic transducer having a different static capacitance requires adifferent tuning inductor L_(t). Moreover, because the tuning inductorL_(t) is matched to the nominal value of the static capacitance C₀ at asingle resonant frequency, accurate control of the motional branchcurrent I_(m)(t) is assured only at that frequency. As frequency shiftsdown with transducer temperature, accurate control of the motionalbranch current is compromised.

Various aspects of the generator 1100 may not rely on a tuning inductorL_(t) to monitor the motional branch current I_(m)(t). Instead, thegenerator 1100 may use the measured value of the static capacitance C₀in between applications of power for a specific ultrasonic surgicaldevice 1104 (along with drive signal voltage and current feedback data)to determine values of the motional branch current I_(m)(t) on a dynamicand ongoing basis (e.g., in real-time). Such aspects of the generator1100 are therefore able to provide virtual tuning to simulate a systemthat is tuned or resonant with any value of static capacitance C₀ at anyfrequency, and not just at a single resonant frequency dictated by anominal value of the static capacitance C₀.

FIG. 26 is a simplified block diagram of one aspect of the generator1100 for providing inductorless tuning as described above, among otherbenefits. FIGS. 27A-27C illustrate an architecture of the generator 1100of FIG. 26 according to one aspect. With reference to FIG. 26 , thegenerator 1100 may comprise a patient isolated stage 1520 incommunication with a non-isolated stage 1540 via a power transformer1560. A secondary winding 1580 of the power transformer 1560 iscontained in the isolated stage 1520 and may comprise a tappedconfiguration (e.g., a center-tapped or non-center tapped configuration)to define drive signal outputs 1600 a, 1600 b, 1600 c for outputtingdrive signals to different surgical devices, such as, for example, anultrasonic surgical device 1104 and an electrosurgical device 1106. Inparticular, drive signal outputs 1600 a, 1600 b, 1600 c may output adrive signal (e.g., a 420V RMS drive signal) to an ultrasonic surgicaldevice 1104, and drive signal outputs 1600 a, 1600 b, 1600 c may outputa drive signal (e.g., a 100V RMS drive signal) to an electrosurgicaldevice 1106, with output 1600 b corresponding to the center tap of thepower transformer 1560. The non-isolated stage 1540 may comprise a poweramplifier 1620 having an output connected to a primary winding 1640 ofthe power transformer 1560. In certain aspects the power amplifier 1620may comprise a push-pull amplifier, for example. The non-isolated stage1540 may further comprise a programmable logic device 1660 for supplyinga digital output to a digital-to-analog converter (DAC) 1680, which inturn supplies a corresponding analog signal to an input of the poweramplifier 1620. In certain aspects the programmable logic device 1660may comprise a field-programmable gate array (FPGA), for example. Theprogrammable logic device 1660, by virtue of controlling the poweramplifier's 1620 input via the DAC 1680, may therefore control any of anumber of parameters (e.g., frequency, waveform shape, waveformamplitude) of drive signals appearing at the drive signal outputs 1600a, 1600 b, 1600 c. In certain aspects and as discussed below, theprogrammable logic device 1660, in conjunction with a processor (e.g.,processor 1740 discussed below), may implement a number of digitalsignal processing (DSP)-based and/or other control algorithms to controlparameters of the drive signals output by the generator 1100.

Power may be supplied to a power rail of the power amplifier 1620 by aswitch-mode regulator 1700. In certain aspects the switch-mode regulator1700 may comprise an adjustable buck regulator, for example. Asdiscussed above, the non-isolated stage 1540 may further comprise aprocessor 1740, which in one aspect may comprise a DSP processor such asan ADSP-21469 SHARC DSP, available from Analog Devices, Norwood, Mass.,for example. In certain aspects the processor 1740 may control operationof the switch-mode power converter 1700 responsive to voltage feedbackdata received from the power amplifier 1620 by the processor 1740 via ananalog-to-digital converter (ADC) 1760. In one aspect, for example, theprocessor 1740 may receive as input, via the ADC 1760, the waveformenvelope of a signal (e.g., an RF signal) being amplified by the poweramplifier 1620. The processor 1740 may then control the switch-moderegulator 1700 (e.g., via a pulse-width modulated (PWM) output) suchthat the rail voltage supplied to the power amplifier 1620 tracks thewaveform envelope of the amplified signal. By dynamically modulating therail voltage of the power amplifier 1620 based on the waveform envelope,the efficiency of the power amplifier 1620 may be significantly improvedrelative to a fixed rail voltage amplifier scheme. The processor 1740may be configured for wired or wireless communication.

In certain aspects and as discussed in further detail in connection withFIGS. 28A-28B, the programmable logic device 1660, in conjunction withthe processor 1740, may implement a direct digital synthesizer (DDS)control scheme to control the waveform shape, frequency and/or amplitudeof drive signals output by the generator 1100. In one aspect, forexample, the programmable logic device 1660 may implement a DDS controlalgorithm 2680 (FIG. 28A) by recalling waveform samples stored in adynamically-updated look-up table (LUT), such as a RAM LUT which may beembedded in an FPGA. This control algorithm is particularly useful forultrasonic applications in which an ultrasonic transducer, such as theultrasonic transducer 1120, may be driven by a clean sinusoidal currentat its resonant frequency. Because other frequencies may exciteparasitic resonances, minimizing or reducing the total distortion of themotional branch current may correspondingly minimize or reduceundesirable resonance effects. Because the waveform shape of a drivesignal output by the generator 1100 is impacted by various sources ofdistortion present in the output drive circuit (e.g., the powertransformer 1560, the power amplifier 1620), voltage and currentfeedback data based on the drive signal may be input into an algorithm,such as an error control algorithm implemented by the processor 1740,which compensates for distortion by suitably pre-distorting or modifyingthe waveform samples stored in the LUT on a dynamic, ongoing basis(e.g., in real-time). In one aspect, the amount or degree ofpre-distortion applied to the LUT samples may be based on the errorbetween a computed motional branch current and a desired currentwaveform shape, with the error being determined on a sample-by samplebasis. In this way, the pre-distorted LUT samples, when processedthrough the drive circuit, may result in a motional branch drive signalhaving the desired waveform shape (e.g., sinusoidal) for optimallydriving the ultrasonic transducer. In such aspects, the LUT waveformsamples will therefore not represent the desired waveform shape of thedrive signal, but rather the waveform shape that is required toultimately produce the desired waveform shape of the motional branchdrive signal when distortion effects are taken into account.

The non-isolated stage 1540 may further comprise an ADC 1780 and an ADC1800 coupled to the output of the power transformer 1560 via respectiveisolation transformers 1820, 1840 for respectively sampling the voltageand current of drive signals output by the generator 1100. In certainaspects, the ADCs 1780, 1800 may be configured to sample at high speeds(e.g., 80 Msps) to enable oversampling of the drive signals. In oneaspect, for example, the sampling speed of the ADCs 1780, 1800 mayenable approximately 200× (depending on drive frequency) oversampling ofthe drive signals. In certain aspects, the sampling operations of theADCs 1780, 1800 may be performed by a single ADC receiving input voltageand current signals via a two-way multiplexer. The use of high-speedsampling in aspects of the generator 1100 may enable, among otherthings, calculation of the complex current flowing through the motionalbranch (which may be used in certain aspects to implement DDS-basedwaveform shape control described above), accurate digital filtering ofthe sampled signals, and calculation of real power consumption with ahigh degree of precision. Voltage and current feedback data output bythe ADCs 1780, 1800 may be received and processed (e.g., FIFO buffering,multiplexing) by the programmable logic device 1660 and stored in datamemory for subsequent retrieval by, for example, the processor 1740. Asnoted above, voltage and current feedback data may be used as input toan algorithm for pre-distorting or modifying LUT waveform samples on adynamic and ongoing basis. In certain aspects, this may require eachstored voltage and current feedback data pair to be indexed based on, orotherwise associated with, a corresponding LUT sample that was output bythe programmable logic device 1660 when the voltage and current feedbackdata pair was acquired. Synchronization of the LUT samples and thevoltage and current feedback data in this manner contributes to thecorrect timing and stability of the pre-distortion algorithm.

In certain aspects, the voltage and current feedback data may be used tocontrol the frequency and/or amplitude (e.g., current amplitude) of thedrive signals. In one aspect, for example, voltage and current feedbackdata may be used to determine impedance phase, e.g., the phasedifference between the voltage and current drive signals. The frequencyof the drive signal may then be controlled to minimize or reduce thedifference between the determined impedance phase and an impedance phasesetpoint (e.g., 0°), thereby minimizing or reducing the effects ofharmonic distortion and correspondingly enhancing impedance phasemeasurement accuracy. The determination of phase impedance and afrequency control signal may be implemented in the processor 1740, forexample, with the frequency control signal being supplied as input to aDDS control algorithm implemented by the programmable logic device 1660.

The impedance phase may be determined through Fourier analysis. In oneaspect, the phase difference between the generator voltage V_(g)(t) andgenerator current I_(g)(t) driving signals may be determined using theFast Fourier Transform (FFT) or the Discrete Fourier Transform (DFT) asfollows:

${{V_{g}(t)} = {A_{1}{\cos\left( {{2\pi f_{0}t} + \varphi_{1}} \right)}}}{{I_{g}(t)} = {A_{2}{\cos\left( {{2\pi f_{0}t} + \varphi_{2}} \right)}}}{{V_{g}(f)} = {\frac{A_{1}}{2}\left( {{\delta\left( {f - f_{0}} \right)} + {\delta\left( {f + f_{0}} \right)}} \right)\exp\left( {j2\pi f\frac{\varphi_{1}}{2\pi f_{0}}} \right)}}{{I_{g}(f)} = {\frac{A_{2}}{2}\left( {{\delta\left( {f - f_{0}} \right)} + {\delta\left( {f + f_{0}} \right)}} \right){\exp\left( {j2\pi f\frac{\varphi_{2}}{2\pi f_{0}}} \right)}}}$

Evaluating the Fourier Transform at the frequency of the sinusoidyields:

$\begin{matrix}{{{V_{g}\left( f_{0} \right)} = {{\frac{A_{1}}{2}{\delta(0)}{\exp\left( {j\varphi_{1}} \right)}\arg{V\left( f_{0} \right)}} = \varphi_{1}}}{{I_{g}\left( f_{0} \right)} = {{\frac{A_{2}}{2}{\delta(0)}\exp\left( {j\varphi_{2}} \right)\arg{I\left( f_{0} \right)}} = \varphi_{2}}}} & \end{matrix}$

Other approaches include weighted least-squares estimation, Kalmanfiltering, and space-vector-based techniques. Virtually all of theprocessing in an FFT or DFT technique may be performed in the digitaldomain with the aid of the 2-channel high speed ADC 1780, 1800, forexample. In one technique, the digital signal samples of the voltage andcurrent signals are Fourier transformed with an FFT or a DFT. The phaseangle φ at any point in time can be calculated by:

φ=2πft+φ ₀

where φ is the phase angle, f is the frequency, t is time, and φ₀ is thephase at t=0.

Another technique for determining the phase difference between thevoltage V_(g)(t) and current I_(g)(t) signals is the zero-crossingmethod and produces highly accurate results. For voltage V_(g)(t) andcurrent I_(g)(t) signals having the same frequency, each negative topositive zero-crossing of voltage signal V_(g)(t) triggers the start ofa pulse, while each negative to positive zero-crossing of current signalI_(g)(t) triggers the end of the pulse. The result is a pulse train witha pulse width proportional to the phase angle between the voltage signaland the current signal. In one aspect, the pulse train may be passedthrough an averaging filter to yield a measure of the phase difference.Furthermore, if the positive to negative zero crossings also are used ina similar manner, and the results averaged, any effects of DC andharmonic components can be reduced. In one implementation, the analogvoltage V_(g)(t) and current I_(g)(t) signals are converted to digitalsignals that are high if the analog signal is positive and low if theanalog signal is negative. High accuracy phase estimates require sharptransitions between high and low. In one aspect, a Schmitt trigger alongwith an RC stabilization network may be employed to convert the analogsignals into digital signals. In other aspects, an edge triggered RSflip-flop and ancillary circuitry may be employed. In yet anotheraspect, the zero-crossing technique may employ an eXclusive OR (XOR)gate.

Other techniques for determining the phase difference between thevoltage and current signals include Lissajous figures and monitoring theimage; methods such as the three-voltmeter method, the crossed-coilmethod, vector voltmeter and vector impedance methods; and using phasestandard instruments, phase-locked loops, and other techniques asdescribed in O'Shea, Peter, “Phase Measurement” 2000 CRC Press LLC,which is incorporated by reference herein in its entirety.

In another aspect, for example, the current feedback data may bemonitored in order to maintain the current amplitude of the drive signalat a current amplitude setpoint. The current amplitude setpoint may bespecified directly or determined indirectly based on specified voltageamplitude and power setpoints. In certain aspects, control of thecurrent amplitude may be implemented by control algorithm, such as, forexample, a proportional-integral-derivative (PID) control algorithm, inthe processor 1740. Variables controlled by the control algorithm tosuitably control the current amplitude of the drive signal may include,for example, the scaling of the LUT waveform samples stored in theprogrammable logic device 1660 and/or the full-scale output voltage ofthe DAC 1680 (which supplies the input to the power amplifier 1620) viaa DAC 1860.

The non-isolated stage 1540 may further comprise a processor 1900 forproviding, among other things, user interface (UI) functionality. In oneaspect, the processor 1900 may comprise an Atmel AT91 SAM9263 processorhaving an ARM 926EJ-S core, available from Atmel Corporation, San Jose,Calif., for example. Examples of UI functionality supported by theprocessor 1900 may include audible and visual user feedback,communication with peripheral devices (e.g., via a Universal Serial Bus(USB) interface), communication with a foot switch 1430, communicationwith an input device 2150 (e.g., a touch screen display) andcommunication with an output device 2140 (e.g., a speaker). Theprocessor 1900 may communicate with the processor 1740 and theprogrammable logic device (e.g., via a serial peripheral interface (SPI)bus). Although the processor 1900 may primarily support UIfunctionality, it may also coordinate with the processor 1740 toimplement hazard mitigation in certain aspects. For example, theprocessor 1900 may be programmed to monitor various aspects of userinput and/or other inputs (e.g., touch screen inputs 2150, foot switch1430 inputs, temperature sensor inputs 2160) and may disable the driveoutput of the generator 1100 when an erroneous condition is detected.

In certain aspects, both the processor 1740 (FIG. 26, 27A) and theprocessor 1900 (FIG. 26, 27B) may determine and monitor the operatingstate of the generator 1100. For processor 1740, the operating state ofthe generator 1100 may dictate, for example, which control and/ordiagnostic processes are implemented by the processor 1740. Forprocessor 1900, the operating state of the generator 1100 may dictate,for example, which elements of a user interface (e.g., display screens,sounds) are presented to a user. The processors 1740, 1900 mayindependently maintain the current operating state of the generator 1100and recognize and evaluate possible transitions out of the currentoperating state. The processor 1740 may function as the master in thisrelationship and determine when transitions between operating states areto occur. The processor 1900 may be aware of valid transitions betweenoperating states and may confirm if a particular transition isappropriate. For example, when the processor 1740 instructs theprocessor 1900 to transition to a specific state, the processor 1900 mayverify that the requested transition is valid. In the event that arequested transition between states is determined to be invalid by theprocessor 1900, the processor 1900 may cause the generator 1100 to entera failure mode.

The non-isolated stage 1540 may further comprise a controller 1960 (FIG.26, 27B) for monitoring input devices 2150 (e.g., a capacitive touchsensor used for turning the generator 1100 on and off, a capacitivetouch screen). In certain aspects, the controller 1960 may comprise atleast one processor and/or other controller device in communication withthe processor 1900. In one aspect, for example, the controller 1960 maycomprise a processor (e.g., a Mega168 8-bit controller available fromAtmel) configured to monitor user input provided via one or morecapacitive touch sensors. In one aspect, the controller 1960 maycomprise a touch screen controller (e.g., a QT5480 touch screencontroller available from Atmel) to control and manage the acquisitionof touch data from a capacitive touch screen.

In certain aspects, when the generator 1100 is in a “power off” state,the controller 1960 may continue to receive operating power (e.g., via aline from a power supply of the generator 1100, such as the power supply2110 (FIG. 26 ) discussed below). In this way, the controller 1960 maycontinue to monitor an input device 2150 (e.g., a capacitive touchsensor located on a front panel of the generator 1100) for turning thegenerator 1100 on and off. When the generator 1100 is in the “power off”state, the controller 1960 may wake the power supply (e.g., enableoperation of one or more DC/DC voltage converters 2130 (FIG. 26 ) of thepower supply 2110) if activation of the “on/off” input device 2150 by auser is detected. The controller 1960 may therefore initiate a sequencefor transitioning the generator 1100 to a “power on” state. Conversely,the controller 1960 may initiate a sequence for transitioning thegenerator 1100 to the “power off” state if activation of the “on/off”input device 2150 is detected when the generator 1100 is in the “poweron” state. In certain aspects, for example, the controller 1960 mayreport activation of the “on/off” input device 2150 to the processor1900, which in turn implements the necessary process sequence fortransitioning the generator 1100 to the “power off” state. In suchaspects, the controller 1960 may have no independent ability for causingthe removal of power from the generator 1100 after its “power on” statehas been established.

In certain aspects, the controller 1960 may cause the generator 1100 toprovide audible or other sensory feedback for alerting the user that a“power on” or “power off” sequence has been initiated. Such an alert maybe provided at the beginning of a “power on” or “power off” sequence andprior to the commencement of other processes associated with thesequence.

In certain aspects, the isolated stage 1520 may comprise an instrumentinterface circuit 1980 to, for example, provide a communicationinterface between a control circuit of a surgical device (e.g., acontrol circuit comprising handpiece switches) and components of thenon-isolated stage 1540, such as, for example, the programmable logicdevice 1660, the processor 1740 and/or the processor 1900. Theinstrument interface circuit 1980 may exchange information withcomponents of the non-isolated stage 1540 via a communication link thatmaintains a suitable degree of electrical isolation between the stages1520, 1540, such as, for example, an infrared (IR)-based communicationlink. Power may be supplied to the instrument interface circuit 1980using, for example, a low-dropout voltage regulator powered by anisolation transformer driven from the non-isolated stage 1540.

In one aspect, the instrument interface circuit 1980 may comprise aprogrammable logic device 2000 (e.g., an FPGA) in communication with asignal conditioning circuit 2020 (FIG. 26 and FIG. 27C). The signalconditioning circuit 2020 may be configured to receive a periodic signalfrom the programmable logic device 2000 (e.g., a 2 kHz square wave) togenerate a bipolar interrogation signal having an identical frequency.The interrogation signal may be generated, for example, using a bipolarcurrent source fed by a differential amplifier. The interrogation signalmay be communicated to a surgical device control circuit (e.g., by usinga conductive pair in a cable that connects the generator 1100 to thesurgical device) and monitored to determine a state or configuration ofthe control circuit. For example, the control circuit may comprise anumber of switches, resistors and/or diodes to modify one or morecharacteristics (e.g., amplitude, rectification) of the interrogationsignal such that a state or configuration of the control circuit isuniquely discernible based on the one or more characteristics. In oneaspect, for example, the signal conditioning circuit 2020 may comprisean ADC for generating samples of a voltage signal appearing acrossinputs of the control circuit resulting from passage of interrogationsignal therethrough. The programmable logic device 2000 (or a componentof the non-isolated stage 1540) may then determine the state orconfiguration of the control circuit based on the ADC samples.

In one aspect, the instrument interface circuit 1980 may comprise afirst data circuit interface 2040 to enable information exchange betweenthe programmable logic device 2000 (or other element of the instrumentinterface circuit 1980) and a first data circuit disposed in orotherwise associated with a surgical device. In certain aspects, forexample, a first data circuit 2060 may be disposed in a cable integrallyattached to a surgical device handpiece, or in an adaptor forinterfacing a specific surgical device type or model with the generator1100. In certain aspects, the first data circuit may comprise anon-volatile storage device, such as an electrically erasableprogrammable read-only memory (EEPROM) device. In certain aspects andreferring again to FIG. 26 , the first data circuit interface 2040 maybe implemented separately from the programmable logic device 2000 andcomprise suitable circuitry (e.g., discrete logic devices, a processor)to enable communication between the programmable logic device 2000 andthe first data circuit. In other aspects, the first data circuitinterface 2040 may be integral with the programmable logic device 2000.

In certain aspects, the first data circuit 2060 may store informationpertaining to the particular surgical device with which it isassociated. Such information may include, for example, a model number, aserial number, a number of operations in which the surgical device hasbeen used, and/or any other type of information. This information may beread by the instrument interface circuit 1980 (e.g., by the programmablelogic device 2000), transferred to a component of the non-isolated stage1540 (e.g., to programmable logic device 1660, processor 1740 and/orprocessor 1900) for presentation to a user via an output device 2140and/or for controlling a function or operation of the generator 1100.Additionally, any type of information may be communicated to first datacircuit 2060 for storage therein via the first data circuit interface2040 (e.g., using the programmable logic device 2000). Such informationmay comprise, for example, an updated number of operations in which thesurgical device has been used and/or dates and/or times of its usage.

As discussed previously, a surgical instrument may be detachable from ahandpiece (e.g., instrument 1106 may be detachable from handpiece 1107)to promote instrument interchangeability and/or disposability. In suchcases, known generators may be limited in their ability to recognizeparticular instrument configurations being used and to optimize controland diagnostic processes accordingly. The addition of readable datacircuits to surgical device instruments to address this issue isproblematic from a compatibility standpoint, however. For example, itmay be impractical to design a surgical device to maintain backwardcompatibility with generators that lack the requisite data readingfunctionality due to, for example, differing signal schemes, designcomplexity and cost. Other aspects of instruments address these concernsby using data circuits that may be implemented in existing surgicalinstruments economically and with minimal design changes to preservecompatibility of the surgical devices with current generator platforms.

Additionally, aspects of the generator 1100 may enable communicationwith instrument-based data circuits. For example, the generator 1100 maybe configured to communicate with a second data circuit (e.g., a datacircuit) contained in an instrument (e.g., instrument 1104, 1106 or1108) of a surgical device. The instrument interface circuit 1980 maycomprise a second data circuit interface 2100 to enable thiscommunication. In one aspect, the second data circuit interface 2100 maycomprise a tri-state digital interface, although other interfaces mayalso be used. In certain aspects, the second data circuit may generallybe any circuit for transmitting and/or receiving data. In one aspect,for example, the second data circuit may store information pertaining tothe particular surgical instrument with which it is associated. Suchinformation may include, for example, a model number, a serial number, anumber of operations in which the surgical instrument has been used,and/or any other type of information. Additionally or alternatively, anytype of information may be communicated to the second data circuit forstorage therein via the second data circuit interface 2100 (e.g., usingthe programmable logic device 2000). Such information may comprise, forexample, an updated number of operations in which the instrument hasbeen used and/or dates and/or times of its usage. In certain aspects,the second data circuit may transmit data acquired by one or moresensors (e.g., an instrument-based temperature sensor). In certainaspects, the second data circuit may receive data from the generator1100 and provide an indication to a user (e.g., an LED indication orother visible indication) based on the received data.

In certain aspects, the second data circuit and the second data circuitinterface 2100 may be configured such that communication between theprogrammable logic device 2000 and the second data circuit can beeffected without the need to provide additional conductors for thispurpose (e.g., dedicated conductors of a cable connecting a handpiece tothe generator 1100). In one aspect, for example, information may becommunicated to and from the second data circuit using a one-wire buscommunication scheme implemented on existing cabling, such as one of theconductors used transmit interrogation signals from the signalconditioning circuit 2020 to a control circuit in a handpiece. In thisway, design changes or modifications to the surgical device that mightotherwise be necessary are minimized or reduced. Moreover, becausedifferent types of communications can be implemented over a commonphysical channel (either with or without frequency-band separation), thepresence of a second data circuit may be “invisible” to generators thatdo not have the requisite data reading functionality, thus enablingbackward compatibility of the surgical device instrument.

In certain aspects, the isolated stage 1520 may comprise at least oneblocking capacitor 2960-1 (FIG. 27C) connected to the drive signaloutput 1600 b to prevent passage of DC current to a patient. A singleblocking capacitor may be required to comply with medical regulations orstandards, for example. While failure in single-capacitor designs isrelatively uncommon, such failure may nonetheless have negativeconsequences. In one aspect, a second blocking capacitor 2960-2 may beprovided in series with the blocking capacitor 2960-1, with currentleakage from a point between the blocking capacitors 2960-1, 2960-2being monitored by, for example, an ADC 2980 for sampling a voltageinduced by leakage current. The samples may be received by theprogrammable logic device 2000, for example. Based on changes in theleakage current (as indicated by the voltage samples in the aspect ofFIG. 26 ), the generator 1100 may determine when at least one of theblocking capacitors 2960-1, 2960-2 has failed. Accordingly, the aspectof FIG. 26 may provide a benefit over single-capacitor designs having asingle point of failure.

In certain aspects, the non-isolated stage 1540 may comprise a powersupply 2110 for outputting DC power at a suitable voltage and current.The power supply may comprise, for example, a 400 W power supply foroutputting a 48 VDC system voltage. As discussed above, the power supply2110 may further comprise one or more DC/DC voltage converters 2130 forreceiving the output of the power supply to generate DC outputs at thevoltages and currents required by the various components of thegenerator 1100. As discussed above in connection with the controller1960, one or more of the DC/DC voltage converters 2130 may receive aninput from the controller 1960 when activation of the “on/off” inputdevice 2150 by a user is detected by the controller 1960 to enableoperation of, or wake, the DC/DC voltage converters 2130.

FIGS. 28A-28B illustrate certain functional and structural aspects ofone aspect of the generator 1100. Feedback indicating current andvoltage output from the secondary winding 1580 of the power transformer1560 is received by the ADCs 1780, 1800, respectively. As shown, theADCs 1780, 1800 may be implemented as a 2-channel ADC and may sample thefeedback signals at a high speed (e.g., 80 Msps) to enable oversampling(e.g., approximately 200× oversampling) of the drive signals. Thecurrent and voltage feedback signals may be suitably conditioned in theanalog domain (e.g., amplified, filtered) prior to processing by theADCs 1780, 1800. Current and voltage feedback samples from the ADCs1780, 1800 may be individually buffered and subsequently multiplexed orinterleaved into a single data stream within block 2120 of theprogrammable logic device 1660. In the aspect of FIGS. 28A-28B, theprogrammable logic device 1660 comprises an FPGA.

The multiplexed current and voltage feedback samples may be received bya parallel data acquisition port (PDAP) implemented within block 2144 ofthe processor 1740. The PDAP may comprise a packing unit forimplementing any of a number of methodologies for correlating themultiplexed feedback samples with a memory address. In one aspect, forexample, feedback samples corresponding to a particular LUT sampleoutput by the programmable logic device 1660 may be stored at one ormore memory addresses that are correlated or indexed with the LUTaddress of the LUT sample. In another aspect, feedback samplescorresponding to a particular LUT sample output by the programmablelogic device 1660 may be stored, along with the LUT address of the LUTsample, at a common memory location. In any event, the feedback samplesmay be stored such that the address of the LUT sample from which aparticular set of feedback samples originated may be subsequentlyascertained. As discussed above, synchronization of the LUT sampleaddresses and the feedback samples in this way contributes to thecorrect timing and stability of the pre-distortion algorithm. A directmemory access (DMA) controller implemented at block 2166 of theprocessor 1740 may store the feedback samples (and any LUT sampleaddress data, where applicable) at a designated memory location 2180 ofthe processor 1740 (e.g., internal RAM).

Block 2200 of the processor 1740 may implement a pre-distortionalgorithm for pre-distorting or modifying the LUT samples stored in theprogrammable logic device 1660 on a dynamic, ongoing basis. As discussedabove, pre-distortion of the LUT samples may compensate for varioussources of distortion present in the output drive circuit of thegenerator 1100. The pre-distorted LUT samples, when processed throughthe drive circuit, will therefore result in a drive signal having thedesired waveform shape (e.g., sinusoidal) for optimally driving theultrasonic transducer.

At block 2220 of the pre-distortion algorithm, the current through themotional branch of the ultrasonic transducer is determined. The motionalbranch current may be determined using Kirchhoff's Current Law based on,for example, the current and voltage feedback samples stored at memorylocation 2180 (which, when suitably scaled, may be representative ofI_(g) and V_(g) in the model of FIG. 25 discussed above), a value of theultrasonic transducer static capacitance C₀ (measured or known a priori)and a known value of the drive frequency. A motional branch currentsample for each set of stored current and voltage feedback samplesassociated with a LUT sample may be determined.

At block 2240 of the pre-distortion algorithm, each motional branchcurrent sample determined at block 2220 is compared to a sample of adesired current waveform shape to determine a difference, or sampleamplitude error, between the compared samples. For this determination,the sample of the desired current waveform shape may be supplied, forexample, from a waveform shape LUT 2260 containing amplitude samples forone cycle of a desired current waveform shape. The particular sample ofthe desired current waveform shape from the LUT 2260 used for thecomparison may be dictated by the LUT sample address associated with themotional branch current sample used in the comparison. Accordingly, theinput of the motional branch current to block 2240 may be synchronizedwith the input of its associated LUT sample address to block 2240. TheLUT samples stored in the programmable logic device 1660 and the LUTsamples stored in the waveform shape LUT 2260 may therefore be equal innumber. In certain aspects, the desired current waveform shaperepresented by the LUT samples stored in the waveform shape LUT 2260 maybe a fundamental sine wave. Other waveform shapes may be desirable. Forexample, it is contemplated that a fundamental sine wave for drivingmain longitudinal motion of an ultrasonic transducer superimposed withone or more other drive signals at other frequencies, such as a thirdorder harmonic for driving at least two mechanical resonances forbeneficial vibrations of transverse or other modes, could be used.

Each value of the sample amplitude error determined at block 2240 may betransmitted to the LUT of the programmable logic device 1660 (shown atblock 2280 in FIG. 28A) along with an indication of its associated LUTaddress. Based on the value of the sample amplitude error and itsassociated address (and, optionally, values of sample amplitude errorfor the same LUT address previously received), the LUT 2280 (or othercontrol block of the programmable logic device 1660) may pre-distort ormodify the value of the LUT sample stored at the LUT address such thatthe sample amplitude error is reduced or minimized. It will beappreciated that such pre-distortion or modification of each LUT samplein an iterative manner across the entire range of LUT addresses willcause the waveform shape of the generator's output current to match orconform to the desired current waveform shape represented by the samplesof the waveform shape LUT 2260.

Current and voltage amplitude measurements, power measurements andimpedance measurements may be determined at block 2300 of the processor1740 based on the current and voltage feedback samples stored at memorylocation 2180. Prior to the determination of these quantities, thefeedback samples may be suitably scaled and, in certain aspects,processed through a suitable filter 2320 to remove noise resulting from,for example, the data acquisition process and induced harmoniccomponents. The filtered voltage and current samples may thereforesubstantially represent the fundamental frequency of the generator'sdrive output signal. In certain aspects, the filter 2320 may be a finiteimpulse response (FIR) filter applied in the frequency domain. Suchaspects may use the Fast Fourier Transform (FFT) of the output drivesignal current and voltage signals. In certain aspects, the resultingfrequency spectrum may be used to provide additional generatorfunctionality. In one aspect, for example, the ratio of the secondand/or third order harmonic component relative to the fundamentalfrequency component may be used as a diagnostic indicator.

At block 2340 (FIG. 28B), a root mean square (RMS) calculation may beapplied to a sample size of the current feedback samples representing anintegral number of cycles of the drive signal to generate a measurementI_(rms) representing the drive signal output current.

At block 2360, a root mean square (RMS) calculation may be applied to asample size of the voltage feedback samples representing an integralnumber of cycles of the drive signal to determine a measurement V_(rms)representing the drive signal output voltage.

At block 2380, the current and voltage feedback samples may bemultiplied point by point, and a mean calculation is applied to samplesrepresenting an integral number of cycles of the drive signal todetermine a measurement P_(r) of the generator's real output power.

At block 2400, measurement P_(a) of the generator's apparent outputpower may be determined as the product V_(rms)·I_(rms).

At block 2420, measurement Z_(m) of the load impedance magnitude may bedetermined as the quotient V_(rms)/I_(rms).

In certain aspects, the quantities I_(rms), V_(rms), P_(r), P_(a) andZ_(m) determined at blocks 2340, 2360, 2380, 2400 and 2420 may be usedby the generator 1100 to implement any of a number of control and/ordiagnostic processes. In certain aspects, any of these quantities may becommunicated to a user via, for example, an output device 2140 integralwith the generator 1100 or an output device 2140 connected to thegenerator 1100 through a suitable communication interface (e.g., a USBinterface). Various diagnostic processes may include, withoutlimitation, handpiece integrity, instrument integrity, instrumentattachment integrity, instrument overload, approaching instrumentoverload, frequency lock failure, over-voltage condition, over-currentcondition, over-power condition, voltage sense failure, current sensefailure, audio indication failure, visual indication failure, shortcircuit condition, power delivery failure, or blocking capacitorfailure, for example.

Block 2440 of the processor 1740 may implement a phase control algorithmfor determining and controlling the impedance phase of an electricalload (e.g., the ultrasonic transducer) driven by the generator 1100. Asdiscussed above, by controlling the frequency of the drive signal tominimize or reduce the difference between the determined impedance phaseand an impedance phase setpoint (e.g., 0°), the effects of harmonicdistortion may be minimized or reduced, and the accuracy of the phasemeasurement increased.

The phase control algorithm receives as input the current and voltagefeedback samples stored in the memory location 2180. Prior to their usein the phase control algorithm, the feedback samples may be suitablyscaled and, in certain aspects, processed through a suitable filter 2460(which may be identical to filter 2320) to remove noise resulting fromthe data acquisition process and induced harmonic components, forexample. The filtered voltage and current samples may thereforesubstantially represent the fundamental frequency of the generator'sdrive output signal.

At block 2480 of the phase control algorithm, the current through themotional branch of the ultrasonic transducer is determined. Thisdetermination may be identical to that described above in connectionwith block 2220 of the pre-distortion algorithm. The output of block2480 may thus be, for each set of stored current and voltage feedbacksamples associated with a LUT sample, a motional branch current sample.

At block 2500 of the phase control algorithm, impedance phase isdetermined based on the synchronized input of motional branch currentsamples determined at block 2480 and corresponding voltage feedbacksamples. In certain aspects, the impedance phase is determined as theaverage of the impedance phase measured at the rising edge of thewaveforms and the impedance phase measured at the falling edge of thewaveforms.

At block 2520 of the of the phase control algorithm, the value of theimpedance phase determined at block 2220 is compared to phase setpoint2540 to determine a difference, or phase error, between the comparedvalues.

At block 2560 (FIG. 28A) of the phase control algorithm, based on avalue of phase error determined at block 2520 and the impedancemagnitude determined at block 2420, a frequency output for controllingthe frequency of the drive signal is determined. The value of thefrequency output may be continuously adjusted by the block 2560 andtransferred to a DDS control block 2680 (discussed below) in order tomaintain the impedance phase determined at block 2500 at the phasesetpoint (e.g., zero phase error). In certain aspects, the impedancephase may be regulated to a 0° phase setpoint. In this way, any harmonicdistortion will be centered about the crest of the voltage waveform,enhancing the accuracy of phase impedance determination.

Block 2580 of the processor 1740 may implement an algorithm formodulating the current amplitude of the drive signal in order to controlthe drive signal current, voltage and power in accordance with userspecified setpoints, or in accordance with requirements specified byother processes or algorithms implemented by the generator 1100. Controlof these quantities may be realized, for example, by scaling the LUTsamples in the LUT 2280 and/or by adjusting the full-scale outputvoltage of the DAC 1680 (which supplies the input to the power amplifier1620) via a DAC 1860. Block 2600 (which may be implemented as a PIDcontroller in certain aspects) may receive, as input, current feedbacksamples (which may be suitably scaled and filtered) from the memorylocation 2180. The current feedback samples may be compared to a“current demand” I_(d) value dictated by the controlled variable (e.g.,current, voltage or power) to determine if the drive signal is supplyingthe necessary current. In aspects in which drive signal current is thecontrol variable, the current demand I_(d) may be specified directly bya current setpoint 2620A (I_(sp)). For example, an RMS value of thecurrent feedback data (determined as in block 2340) may be compared touser-specified RMS current setpoint I_(sp) to determine the appropriatecontroller action. If, for example, the current feedback data indicatesan RMS value less than the current setpoint I_(sp), LUT scaling and/orthe full-scale output voltage of the DAC 1680 may be adjusted by theblock 2600 such that the drive signal current is increased. Conversely,block 2600 may adjust LUT scaling and/or the full-scale output voltageof the DAC 1680 to decrease the drive signal current when the currentfeedback data indicates an RMS value greater than the current setpointI_(sp).

In aspects in which the drive signal voltage is the control variable,the current demand I_(d) may be specified indirectly, for example, basedon the current required to maintain a desired voltage setpoint 2620B(V_(sp)) given the load impedance magnitude Z_(m) measured at block 2420(e.g. I_(d)=V_(sp)/Z_(m)). Similarly, in aspects in which drive signalpower is the control variable, the current demand I_(d) may be specifiedindirectly, for example, based on the current required to maintain adesired power setpoint 2620C (P_(sp)) given the voltage V_(rms) measuredat blocks 2360 (e.g. I_(d)=P_(sp)V_(rms)).

Block 2680 (FIG. 28A) may implement a DDS control algorithm forcontrolling the drive signal by recalling LUT samples stored in the LUT2280. In certain aspects, the DDS control algorithm may be anumerically-controlled oscillator (NCO) algorithm for generating samplesof a waveform at a fixed clock rate using a point (memorylocation)-skipping technique. The NCO algorithm may implement a phaseaccumulator, or frequency-to-phase converter, that functions as anaddress pointer for recalling LUT samples from the LUT 2280. In oneaspect, the phase accumulator may be a D step size, modulo N phaseaccumulator, where D is a positive integer representing a frequencycontrol value, and N is the number of LUT samples in the LUT 2280. Afrequency control value of D=1, for example, may cause the phaseaccumulator to sequentially point to every address of the LUT 2280,resulting in a waveform output replicating the waveform stored in theLUT 2280. When D>1, the phase accumulator may skip addresses in the LUT2280, resulting in a waveform output having a higher frequency.Accordingly, the frequency of the waveform generated by the DDS controlalgorithm may therefore be controlled by suitably varying the frequencycontrol value. In certain aspects, the frequency control value may bedetermined based on the output of the phase control algorithmimplemented at block 2440. The output of block 2680 may supply the inputof DAC 1680, which in turn supplies a corresponding analog signal to aninput of the power amplifier 1620.

Block 2700 of the processor 1740 may implement a switch-mode convertercontrol algorithm for dynamically modulating the rail voltage of thepower amplifier 1620 based on the waveform envelope of the signal beingamplified, thereby improving the efficiency of the power amplifier 1620.In certain aspects, characteristics of the waveform envelope may bedetermined by monitoring one or more signals contained in the poweramplifier 1620. In one aspect, for example, characteristics of thewaveform envelope may be determined by monitoring the minima of a drainvoltage (e.g., a MOSFET drain voltage) that is modulated in accordancewith the envelope of the amplified signal. A minima voltage signal maybe generated, for example, by a voltage minima detector coupled to thedrain voltage. The minima voltage signal may be sampled by ADC 1760,with the output minima voltage samples being received at block 2720 ofthe switch-mode converter control algorithm. Based on the values of theminima voltage samples, block 2740 may control a PWM signal output by aPWM generator 2760, which, in turn, controls the rail voltage suppliedto the power amplifier 1620 by the switch-mode regulator 1700. Incertain aspects, as long as the values of the minima voltage samples areless than a minima target 2780 input into block 2720, the rail voltagemay be modulated in accordance with the waveform envelope ascharacterized by the minima voltage samples. When the minima voltagesamples indicate low envelope power levels, for example, block 2740 maycause a low rail voltage to be supplied to the power amplifier 1620,with the full rail voltage being supplied only when the minima voltagesamples indicate maximum envelope power levels. When the minima voltagesamples fall below the minima target 2780, block 2740 may cause the railvoltage to be maintained at a minimum value suitable for ensuring properoperation of the power amplifier 1620.

FIG. 29 is a schematic diagram of one aspect of an electrical circuit2900, suitable for driving an ultrasonic transducer, such as ultrasonictransducer 1120, in accordance with at least one aspect of the presentdisclosure. The electrical circuit 2900 comprises an analog multiplexer2980. The analog multiplexer 2980 multiplexes various signals from theupstream channels SCL-A, SDA-A such as ultrasonic, battery, and powercontrol circuit. A current sensor 2982 is coupled in series with thereturn or ground leg of the power supply circuit to measure the currentsupplied by the power supply. A field effect transistor (FET)temperature sensor 2984 provides the ambient temperature. A pulse widthmodulation (PWM) watchdog timer 2988 automatically generates a systemreset if the main program neglects to periodically service it. It isprovided to automatically reset the electrical circuit 2900 when ithangs or freezes because of a software or hardware fault. It will beappreciated that the electrical circuit 2900 may be configured as an RFdriver circuit for driving the ultrasonic transducer or for driving RFelectrodes such as the electrical circuit 3600 shown in FIG. 36 , forexample. Accordingly, with reference now back to FIG. 29 , theelectrical circuit 2900 can be used to drive both ultrasonic transducersand RF electrodes interchangeably. If driven simultaneously, filtercircuits may be provided in the corresponding first stage circuits 3404(FIG. 34 ) to select either the ultrasonic waveform or the RF waveform.Such filtering techniques are described in commonly owned U.S. Pat. Pub.No. US-2017-0086910-A1, titled TECHNIQUES FOR CIRCUIT TOPOLOGIES FORCOMBINED GENERATOR, which is herein incorporated by reference in itsentirety.

A drive circuit 2986 provides left and right ultrasonic energy outputs.A digital signal that represents the signal waveform is provided to theSCL-A, SDA-A inputs of the analog multiplexer 2980 from a controlcircuit, such as the control circuit 3200 (FIG. 32 ). Adigital-to-analog converter 2990 (DAC) converts the digital input to ananalog output to drive a PWM circuit 2992 coupled to an oscillator 2994.The PWM circuit 2992 provides a first signal to a first gate drivecircuit 2996 a coupled to a first transistor output stage 2998 a todrive a first Ultrasonic (LEFT) energy output. The PWM circuit 2992 alsoprovides a second signal to a second gate drive circuit 2996 b coupledto a second transistor output stage 2998 b to drive a second Ultrasonic(RIGHT) energy output. A voltage sensor 2999 is coupled between theUltrasonic LEFT/RIGHT output terminals to measure the output voltage.The drive circuit 2986, the first and second drive circuits 2996 a, 2996b, and the first and second transistor output stages 2998 a, 2998 bdefine a first stage amplifier circuit. In operation, the controlcircuit 3200 (FIG. 32 ) generates a digital waveform 4300 (FIG. 43 )employing circuits such as direct digital synthesis (DDS) circuits 4100,4200 (FIGS. 41 and 42 ). The DAC 2990 receives the digital waveform 4300and converts it into an analog waveform, which is received and amplifiedby the first stage amplifier circuit.

FIG. 30 is a schematic diagram of the transformer 3000 coupled to theelectrical circuit 2900 shown in FIG. 29 , in accordance with at leastone aspect of the present disclosure. The Ultrasonic LEFT/RIGHT inputterminals (primary winding) of the transformer 3000 are electricallycoupled to the Ultrasonic LEFT/RIGHT output terminals of the electricalcircuit 2900. The secondary winding of the transformer 3000 are coupledto the positive and negative electrodes 3074 a, 3074 b. The positive andnegative electrodes 3074 a, 3074 b of the transformer 3000 are coupledto the positive terminal (Stack 1) and the negative terminal (Stack 2)of an ultrasonic transducer. In one aspect, the transformer 3000 has aturns-ratio of n₁:n₂ of 1:50.

FIG. 31 is a schematic diagram of the transformer 3000 shown in FIG. 30coupled to a test circuit 3165, in accordance with at least one aspectof the present disclosure. The test circuit 3165 is coupled to thepositive and negative electrodes 3074 a, 3074 b. A switch 3167 is placedin series with an inductor/capacitor/resistor (LCR) load that simulatesthe load of an ultrasonic transducer.

FIG. 32 is a schematic diagram of a control circuit 3200, such ascontrol circuit 3212, in accordance with at least one aspect of thepresent disclosure. The control circuit 3200 is located within a housingof the battery assembly. The battery assembly is the energy source for avariety of local power supplies 3215. The control circuit comprises amain processor 3214 coupled via an interface master 3218 to variousdownstream circuits by way of outputs SCL-A and SDA-A, SCL-B and SDA-B,SCL-C and SDA-C, for example. In one aspect, the interface master 3218is a general purpose serial interface such as an I²C serial interface.The main processor 3214 also is configured to drive switches 3224through general purposes input/output (GPIO) 3220, a display 3226 (e.g.,and LCD display), and various indicators 3228 through GPIO 3222. Awatchdog processor 3216 is provided to control the main processor 3214.A switch 3230 is provided in series with a battery 3211 to activate thecontrol circuit 3212 upon insertion of the battery assembly into ahandle assembly of a surgical instrument.

In one aspect, the main processor 3214 is coupled to the electricalcircuit 2900 (FIG. 29 ) by way of output terminals SCL-A, SDA-A. Themain processor 3214 comprises a memory for storing tables of digitizeddrive signals or waveforms that are transmitted to the electricalcircuit 2900 for driving the ultrasonic transducer 1120, for example. Inother aspects, the main processor 3214 may generate a digital waveformand transmit it to the electrical circuit 2900 or may store the digitalwaveform for later transmission to the electrical circuit 2900. The mainprocessor 3214 also may provide RF drive by way of output terminalsSCL-B, SDA-B and various sensors (e.g., Hall-effect sensors,magneto-rheological fluid (MRF) sensors, etc.) by way of outputterminals SCL-C, SDA-C. In one aspect, the main processor 3214 isconfigured to sense the presence of ultrasonic drive circuitry and/or RFdrive circuitry to enable appropriate software and user interfacefunctionality.

In one aspect, the main processor 3214 may be an LM 4F230H5QR, availablefrom Texas Instruments, for example. In at least one example, the TexasInstruments LM4F230H5QR is an ARM Cortex-M4F Processor Core comprisingon-chip memory of 256 KB single-cycle flash memory, or othernon-volatile memory, up to 40 MHz, a prefetch buffer to improveperformance above 40 MHz, a 32 KB single-cycle serial random accessmemory (SRAM), internal read-only memory (ROM) loaded withStellarisWare® software, 2 KB electrically erasable programmableread-only memory (EEPROM), one or more pulse width modulation (PWM)modules, one or more quadrature encoder inputs (QED analog, one or more12-bit Analog-to-Digital Converters (ADC) with 12 analog input channels,among other features that are readily available from the productdatasheet. Other processors may be readily substituted and, accordingly,the present disclosure should not be limited in this context.

FIG. 33 shows a simplified block circuit diagram illustrating anotherelectrical circuit 3300 contained within a modular ultrasonic surgicalinstrument 3334, in accordance with at least one aspect of the presentdisclosure. The electrical circuit 3300 includes a processor 3302, aclock 3330, a memory 3326, a power supply 3304 (e.g., a battery), aswitch 3306, such as a metal-oxide semiconductor field effect transistor(MOSFET) power switch, a drive circuit 3308 (PLL), a transformer 3310, asignal smoothing circuit 3312 (also referred to as a matching circuitand can be, for example, a tank circuit), a sensing circuit 3314, atransducer 1120, and a shaft assembly (e.g. shaft assembly 1126, 1129)comprising an ultrasonic transmission waveguide that terminates at anultrasonic blade (e.g. ultrasonic blade 1128, 1149) which may bereferred to herein simply as the waveguide.

One feature of the present disclosure that severs dependency on highvoltage (120 VAC) input power (a characteristic of general ultrasoniccutting devices) is the utilization of low-voltage switching throughoutthe wave-forming process and the amplification of the driving signalonly directly before the transformer stage. For this reason, in oneaspect of the present disclosure, power is derived from only a battery,or a group of batteries, small enough to fit either within a handleassembly. State-of-the-art battery technology provides powerfulbatteries of a few centimeters in height and width and a few millimetersin depth. By combining the features of the present disclosure to providea self-contained and self-powered ultrasonic device, a reduction inmanufacturing cost may be achieved.

The output of the power supply 3304 is fed to and powers the processor3302. The processor 3302 receives and outputs signals and, as will bedescribed below, functions according to custom logic or in accordancewith computer programs that are executed by the processor 3302. Asdiscussed above, the electrical circuit 3300 can also include a memory3326, preferably, random access memory (RAM), that storescomputer-readable instructions and data.

The output of the power supply 3304 also is directed to the switch 3306having a duty cycle controlled by the processor 3302. By controlling theon-time for the switch 3306, the processor 3302 is able to dictate thetotal amount of power that is ultimately delivered to the transducer1120. In one aspect, the switch 3306 is a MOSFET, although otherswitches and switching configurations are adaptable as well. The outputof the switch 3306 is fed to a drive circuit 3308 that contains, forexample, a phase detecting phase-locked loop (PLL) and/or a low-passfilter and/or a voltage-controlled oscillator. The output of the switch3306 is sampled by the processor 3302 to determine the voltage andcurrent of the output signal (V_(IN) and I_(IN), respectively). Thesevalues are used in a feedback architecture to adjust the pulse widthmodulation of the switch 3306. For instance, the duty cycle of theswitch 3306 can vary from about 20% to about 80%, depending on thedesired and actual output from the switch 3306.

The drive circuit 3308, which receives the signal from the switch 3306,includes an oscillatory circuit that turns the output of the switch 3306into an electrical signal having an ultrasonic frequency, e.g., 55 kHz(VCO). As explained above, a smoothed-out version of this ultrasonicwaveform is ultimately fed to the ultrasonic transducer 1120 to producea resonant sine wave along an ultrasonic transmission waveguide.

At the output of the drive circuit 3308 is a transformer 3310 that isable to step up the low voltage signal(s) to a higher voltage. It isnoted that upstream switching, prior to the transformer 3310, isperformed at low (e.g., battery driven) voltages, something that, todate, has not been possible for ultrasonic cutting and cautery devices.This is at least partially due to the fact that the deviceadvantageously uses low on-resistance MOSFET switching devices. Lowon-resistance MOSFET switches are advantageous, as they produce lowerswitching losses and less heat than a traditional MOSFET device andallow higher current to pass through. Therefore, the switching stage(pre-transformer) can be characterized as low voltage/high current. Toensure the lower on-resistance of the amplifier MOSFET(s), the MOSFET(s)are run, for example, at 10 V. In such a case, a separate 10 VDC powersupply can be used to feed the MOSFET gate, which ensures that theMOSFET is fully on and a reasonably low on resistance is achieved. Inone aspect of the present disclosure, the transformer 3310 steps up thebattery voltage to 120 V root-mean-square (RMS). Transformers are knownin the art and are, therefore, not explained here in detail.

In the circuit configurations described, circuit component degradationcan negatively impact the circuit performance of the circuit. One factorthat directly affects component performance is heat. Known circuitsgenerally monitor switching temperatures (e.g., MOSFET temperatures).However, because of the technological advancements in MOSFET designs,and the corresponding reduction in size, MOSFET temperatures are nolonger a valid indicator of circuit loads and heat. For this reason, inaccordance with at least one aspect of the present disclosure, thesensing circuit 3314 senses the temperature of the transformer 3310.This temperature sensing is advantageous as the transformer 3310 is runat or very close to its maximum temperature during use of the device.Additional temperature will cause the core material, e.g., the ferrite,to break down and permanent damage can occur. The present disclosure canrespond to a maximum temperature of the transformer 3310 by, forexample, reducing the driving power in the transformer 3310, signalingthe user, turning the power off, pulsing the power, or other appropriateresponses.

In one aspect of the present disclosure, the processor 3302 iscommunicatively coupled to the end effector (e.g. 1122, 1125), which isused to place material in physical contact with the ultrasonic blade(e.g. 1128, 1149). Sensors are provided that measure, at the endeffector, a clamping force value (existing within a known range) and,based upon the received clamping force value, the processor 3302 variesthe motional voltage V_(M). Because high force values combined with aset motional rate can result in high blade temperatures, a temperaturesensor 3332 can be communicatively coupled to the processor 3302, wherethe processor 3302 is operable to receive and interpret a signalindicating a current temperature of the blade from the temperaturesensor 3336 and to determine a target frequency of blade movement basedupon the received temperature. In another aspect, force sensors such asstrain gages or pressure sensors may be coupled to the trigger (e.g.1143, 1147) to measure the force applied to the trigger by the user. Inanother aspect, force sensors such as strain gages or pressure sensorsmay be coupled to a switch button such that displacement intensitycorresponds to the force applied by the user to the switch button.

In accordance with at least one aspect of the present disclosure, thePLL portion of the drive circuit 3308, which is coupled to the processor3302, is able to determine a frequency of waveguide movement andcommunicate that frequency to the processor 3302. The processor 3302stores this frequency value in the memory 3326 when the device is turnedoff. By reading the clock 3330, the processor 3302 is able to determinean elapsed time after the device is shut off and retrieve the lastfrequency of waveguide movement if the elapsed time is less than apredetermined value. The device can then start up at the last frequency,which, presumably, is the optimum frequency for the current load.

Modular Battery Powered Handheld Surgical Instrument with MultistageGenerator Circuits

In another aspect, the present disclosure provides a modular batterypowered handheld surgical instrument with multistage generator circuits.Disclosed is a surgical instrument that includes a battery assembly, ahandle assembly, and a shaft assembly where the battery assembly and theshaft assembly are configured to mechanically and electrically connectto the handle assembly. The battery assembly includes a control circuitconfigured to generate a digital waveform. The handle assembly includesa first stage circuit configured to receive the digital waveform,convert the digital waveform into an analog waveform, and amplify theanalog waveform. The shaft assembly includes a second stage circuitcoupled to the first stage circuit to receive, amplify, and apply theanalog waveform to a load.

In one aspect, the present disclosure provides a surgical instrument,comprising: a battery assembly, comprising a control circuit comprisinga battery, a memory coupled to the battery, and a processor coupled tothe memory and the battery, wherein the processor is configured togenerate a digital waveform; a handle assembly comprising a first stagecircuit coupled to the processor, the first stage circuit comprising adigital-to-analog (DAC) converter and a first stage amplifier circuit,wherein the DAC is configured to receive the digital waveform andconvert the digital waveform into an analog waveform, wherein the firststage amplifier circuit is configured to receive and amplify the analogwaveform; and a shaft assembly comprising a second stage circuit coupledto the first stage amplifier circuit to receive the analog waveform,amplify the analog waveform, and apply the analog waveform to a load;wherein the battery assembly and the shaft assembly are configured tomechanically and electrically connect to the handle assembly.

The load may comprise any one of an ultrasonic transducer, an electrode,or a sensor, or any combinations thereof. The first stage circuit maycomprise a first stage ultrasonic drive circuit and a first stagehigh-frequency current drive circuit. The control circuit may beconfigured to drive the first stage ultrasonic drive circuit and thefirst stage high-frequency current drive circuit independently orsimultaneously. The first stage ultrasonic drive circuit may beconfigured to couple to a second stage ultrasonic drive circuit. Thesecond stage ultrasonic drive circuit may be configured to couple to anultrasonic transducer. The first stage high-frequency current drivecircuit may be configured to couple to a second stage high-frequencydrive circuit. The second stage high-frequency drive circuit may beconfigured to couple to an electrode.

The first stage circuit may comprise a first stage sensor drive circuit.The first stage sensor drive circuit may be configured to a second stagesensor drive circuit. The second stage sensor drive circuit may beconfigured to couple to a sensor.

In another aspect, the present disclosure provides a surgicalinstrument, comprising: a battery assembly, comprising a control circuitcomprising a battery, a memory coupled to the battery, and a processorcoupled to the memory and the battery, wherein the processor isconfigured to generate a digital waveform; a handle assembly comprisinga common first stage circuit coupled to the processor, the common firststage circuit comprising a digital-to-analog (DAC) converter and acommon first stage amplifier circuit, wherein the DAC is configured toreceive the digital waveform and convert the digital waveform into ananalog waveform, wherein the common first stage amplifier circuit isconfigured to receive and amplify the analog waveform; and a shaftassembly comprising a second stage circuit coupled to the common firststage amplifier circuit to receive the analog waveform, amplify theanalog waveform, and apply the analog waveform to a load; wherein thebattery assembly and the shaft assembly are configured to mechanicallyand electrically connect to the handle assembly.

The load may comprise any one of an ultrasonic transducer, an electrode,or a sensor, or any combinations thereof. The common first stage circuitmay be configured to drive ultrasonic, high-frequency current, or sensorcircuits. The common first stage drive circuit may be configured tocouple to a second stage ultrasonic drive circuit, a second stagehigh-frequency drive circuit, or a second stage sensor drive circuit.The second stage ultrasonic drive circuit may be configured to couple toan ultrasonic transducer, the second stage high-frequency drive circuitis configured to couple to an electrode, and the second stage sensordrive circuit is configured to couple to a sensor.

In another aspect, the present disclosure provides a surgicalinstrument, comprising a control circuit comprising a memory coupled toa processor, wherein the processor is configured to generate a digitalwaveform; a handle assembly comprising a common first stage circuitcoupled to the processor, the common first stage circuit configured toreceive the digital waveform, convert the digital waveform into ananalog waveform, and amplify the analog waveform; and a shaft assemblycomprising a second stage circuit coupled to the common first stagecircuit to receive and amplify the analog waveform; wherein the shaftassembly is configured to mechanically and electrically connect to thehandle assembly.

The common first stage circuit may be configured to drive ultrasonic,high-frequency current, or sensor circuits. The common first stage drivecircuit may be configured to couple to a second stage ultrasonic drivecircuit, a second stage high-frequency drive circuit, or a second stagesensor drive circuit. The second stage ultrasonic drive circuit may beconfigured to couple to an ultrasonic transducer, the second stagehigh-frequency drive circuit is configured to couple to an electrode,and the second stage sensor drive circuit is configured to couple to asensor.

FIG. 34 illustrates a generator circuit 3400 partitioned into a firststage circuit 3404 and a second stage circuit 3406, in accordance withat least one aspect of the present disclosure. In one aspect, thesurgical instruments of surgical system 1000 described herein maycomprise a generator circuit 3400 partitioned into multiple stages. Forexample, surgical instruments of surgical system 1000 may comprise thegenerator circuit 3400 partitioned into at least two circuits: the firststage circuit 3404 and the second stage circuit 3406 of amplificationenabling operation of RF energy only, ultrasonic energy only, and/or acombination of RF energy and ultrasonic energy. A combination modularshaft assembly 3414 may be powered by the common first stage circuit3404 located within a handle assembly 3412 and the modular second stagecircuit 3406 integral to the modular shaft assembly 3414. As previouslydiscussed throughout this description in connection with the surgicalinstruments of surgical system 1000, a battery assembly 3410 and theshaft assembly 3414 are configured to mechanically and electricallyconnect to the handle assembly 3412. The end effector assembly isconfigured to mechanically and electrically connect the shaft assembly3414.

Turning now to FIG. 34 , the generator circuit 3400 is partitioned intomultiple stages located in multiple modular assemblies of a surgicalinstrument, such as the surgical instruments of surgical system 1000described herein. In one aspect, a control stage circuit 3402 may belocated in the battery assembly 3410 of the surgical instrument. Thecontrol stage circuit 3402 is a control circuit 3200 as described inconnection with FIG. 32 . The control circuit 3200 comprises a processor3214, which includes internal memory 3217 (FIG. 34 ) (e.g., volatile andnon-volatile memory), and is electrically coupled to a battery 3211. Thebattery 3211 supplies power to the first stage circuit 3404, the secondstage circuit 3406, and a third stage circuit 3408, respectively. Aspreviously discussed, the control circuit 3200 generates a digitalwaveform 4300 (FIG. 43 ) using circuits and techniques described inconnection with FIGS. 41 and 42 . Returning to FIG. 34 , the digitalwaveform 4300 may be configured to drive an ultrasonic transducer,high-frequency (e.g., RF) electrodes, or a combination thereof eitherindependently or simultaneously. If driven simultaneously, filtercircuits may be provided in the corresponding first stage circuits 3404to select either the ultrasonic waveform or the RF waveform. Suchfiltering techniques are described in commonly owned U.S. Pat. Pub. No.US-2017-0086910-A1, titled TECHNIQUES FOR CIRCUIT TOPOLOGIES FORCOMBINED GENERATOR, which is herein incorporated by reference in itsentirety.

The first stage circuits 3404 (e.g., the first stage ultrasonic drivecircuit 3420, the first stage RF drive circuit 3422, and the first stagesensor drive circuit 3424) are located in a handle assembly 3412 of thesurgical instrument. The control circuit 3200 provides the ultrasonicdrive signal to the first stage ultrasonic drive circuit 3420 viaoutputs SCL-A, SDA-A of the control circuit 3200. The first stageultrasonic drive circuit 3420 is described in detail in connection withFIG. 29 . The control circuit 3200 provides the RF drive signal to thefirst stage RF drive circuit 3422 via outputs SCL-B, SDA-B of thecontrol circuit 3200. The first stage RF drive circuit 3422 is describedin detail in connection with FIG. 36 . The control circuit 3200 providesthe sensor drive signal to the first stage sensor drive circuit 3424 viaoutputs SCL-C, SDA-C of the control circuit 3200. Generally, each of thefirst stage circuits 3404 includes a digital-to-analog (DAC) converterand a first stage amplifier section to drive the second stage circuits3406. The outputs of the first stage circuits 3404 are provided to theinputs of the second stage circuits 3406.

The control circuit 3200 is configured to detect which modules areplugged into the control circuit 3200. For example, the control circuit3200 is configured to detect whether the first stage ultrasonic drivecircuit 3420, the first stage RF drive circuit 3422, or the first stagesensor drive circuit 3424 located in the handle assembly 3412 isconnected to the battery assembly 3410. Likewise, each of the firststage circuits 3404 can detect which second stage circuits 3406 areconnected thereto and that information is provided back to the controlcircuit 3200 to determine the type of signal waveform to generate.Similarly, each of the second stage circuits 3406 can detect which thirdstage circuits 3408 or components are connected thereto and thatinformation is provided back to the control circuit 3200 to determinethe type of signal waveform to generate.

In one aspect, the second stage circuits 3406 (e.g., the ultrasonicdrive second stage circuit 3430, the RF drive second stage circuit 3432,and the sensor drive second stage circuit 3434) are located in the shaftassembly 3414 of the surgical instrument. The first stage ultrasonicdrive circuit 3420 provides a signal to the second stage ultrasonicdrive circuit 3430 via outputs US-Left/US-Right. The second stageultrasonic drive circuit 3430 is described in detail in connection withFIGS. 30 and 31 . In addition to a transformer (FIGS. 30 and 31 ), thesecond stage ultrasonic drive circuit 3430 also may include filter,amplifier, and signal conditioning circuits. The first stagehigh-frequency (RF) current drive circuit 3422 provides a signal to thesecond stage RF drive circuit 3432 via outputs RF-Left/RF-Right. Inaddition to a transformer and blocking capacitors, the second stage RFdrive circuit 3432 also may include filter, amplifier, and signalconditioning circuits. The first stage sensor drive circuit 3424provides a signal to the second stage sensor drive circuit 3434 viaoutputs Sensor-1/Sensor-2. The second stage sensor drive circuit 3434may include filter, amplifier, and signal conditioning circuitsdepending on the type of sensor. The outputs of the second stagecircuits 3406 are provided to the inputs of the third stage circuits3408.

In one aspect, the third stage circuits 3408 (e.g., the ultrasonictransducer 1120, the RF electrodes 3074 a, 3074 b, and the sensors 3440)may be located in various assemblies 3416 of the surgical instruments.In one aspect, the second stage ultrasonic drive circuit 3430 provides adrive signal to the ultrasonic transducer 1120 piezoelectric stack. Inone aspect, the ultrasonic transducer 1120 is located in the ultrasonictransducer assembly of the surgical instrument. In other aspects,however, the ultrasonic transducer 1120 may be located in the handleassembly 3412, the shaft assembly 3414, or the end effector. In oneaspect, the second stage RF drive circuit 3432 provides a drive signalto the RF electrodes 3074 a, 3074 b, which are generally located in theend effector portion of the surgical instrument. In one aspect, thesecond stage sensor drive circuit 3434 provides a drive signal tovarious sensors 3440 located throughout the surgical instrument.

FIG. 35 illustrates a generator circuit 3500 partitioned into multiplestages where a first stage circuit 3504 is common to the second stagecircuit 3506, in accordance with at least one aspect of the presentdisclosure. In one aspect, the surgical instruments of surgical system1000 described herein may comprise generator circuit 3500 partitionedinto multiple stages. For example, the surgical instruments of surgicalsystem 1000 may comprise the generator circuit 3500 partitioned into atleast two circuits: the first stage circuit 3504 and the second stagecircuit 3506 of amplification enabling operation of high-frequency (RF)energy only, ultrasonic energy only, and/or a combination of RF energyand ultrasonic energy. A combination modular shaft assembly 3514 may bepowered by a common first stage circuit 3504 located within the handleassembly 3512 and a modular second stage circuit 3506 integral to themodular shaft assembly 3514. As previously discussed throughout thisdescription in connection with the surgical instruments of surgicalsystem 1000, a battery assembly 3510 and the shaft assembly 3514 areconfigured to mechanically and electrically connect to the handleassembly 3512. The end effector assembly is configured to mechanicallyand electrically connect the shaft assembly 3514.

As shown in the example of FIG. 35 , the battery assembly 3510 portionof the surgical instrument comprises a first control circuit 3502, whichincludes the control circuit 3200 previously described. The handleassembly 3512, which connects to the battery assembly 3510, comprises acommon first stage drive circuit 3420. As previously discussed, thefirst stage drive circuit 3420 is configured to drive ultrasonic,high-frequency (RF) current, and sensor loads. The output of the commonfirst stage drive circuit 3420 can drive any one of the second stagecircuits 3506 such as the second stage ultrasonic drive circuit 3430,the second stage high-frequency (RF) current drive circuit 3432, and/orthe second stage sensor drive circuit 3434. The common first stage drivecircuit 3420 detects which second stage circuit 3506 is located in theshaft assembly 3514 when the shaft assembly 3514 is connected to thehandle assembly 3512. Upon the shaft assembly 3514 being connected tothe handle assembly 3512, the common first stage drive circuit 3420determines which one of the second stage circuits 3506 (e.g., the secondstage ultrasonic drive circuit 3430, the second stage RF drive circuit3432, and/or the second stage sensor drive circuit 3434) is located inthe shaft assembly 3514. The information is provided to the controlcircuit 3200 located in the handle assembly 3512 in order to supply asuitable digital waveform 4300 (FIG. 43 ) to the second stage circuit3506 to drive the appropriate load, e.g., ultrasonic, RF, or sensor. Itwill be appreciated that identification circuits may be included invarious assemblies 3516 in third stage circuit 3508 such as theultrasonic transducer 1120, the electrodes 3074 a, 3074 b, or thesensors 3440. Thus, when a third stage circuit 3508 is connected to asecond stage circuit 3506, the second stage circuit 3506 knows the typeof load that is required based on the identification information.

FIG. 36 is a schematic diagram of one aspect of an electrical circuit3600 configured to drive a high-frequency current (RF), in accordancewith at least one aspect of the present disclosure. The electricalcircuit 3600 comprises an analog multiplexer 3680. The analogmultiplexer 3680 multiplexes various signals from the upstream channelsSCL-A, SDA-A such as RF, battery, and power control circuit. A currentsensor 3682 is coupled in series with the return or ground leg of thepower supply circuit to measure the current supplied by the powersupply. A field effect transistor (FET) temperature sensor 3684 providesthe ambient temperature. A pulse width modulation (PWM) watchdog timer3688 automatically generates a system reset if the main program neglectsto periodically service it. It is provided to automatically reset theelectrical circuit 3600 when it hangs or freezes because of a softwareor hardware fault. It will be appreciated that the electrical circuit3600 may be configured for driving RF electrodes or for driving theultrasonic transducer 1120 as described in connection with FIG. 29 , forexample. Accordingly, with reference now back to FIG. 36 , theelectrical circuit 3600 can be used to drive both ultrasonic and RFelectrodes interchangeably.

A drive circuit 3686 provides Left and Right RF energy outputs. Adigital signal that represents the signal waveform is provided to theSCL-A, SDA-A inputs of the analog multiplexer 3680 from a controlcircuit, such as the control circuit 3200 (FIG. 32 ). Adigital-to-analog converter 3690 (DAC) converts the digital input to ananalog output to drive a PWM circuit 3692 coupled to an oscillator 3694.The PWM circuit 3692 provides a first signal to a first gate drivecircuit 3696 a coupled to a first transistor output stage 3698 a todrive a first RF+ (Left) energy output. The PWM circuit 3692 alsoprovides a second signal to a second gate drive circuit 3696 b coupledto a second transistor output stage 3698 b to drive a second RF− (Right)energy output. A voltage sensor 3699 is coupled between the RF Left/RFoutput terminals to measure the output voltage. The drive circuit 3686,the first and second drive circuits 3696 a, 3696 b, and the first andsecond transistor output stages 3698 a, 3698 b define a first stageamplifier circuit. In operation, the control circuit 3200 (FIG. 32 )generates a digital waveform 4300 (FIG. 43 ) employing circuits such asdirect digital synthesis (DDS) circuits 4100, 4200 (FIGS. 41 and 42 ).The DAC 3690 receives the digital waveform 4300 and converts it into ananalog waveform, which is received and amplified by the first stageamplifier circuit.

FIG. 37 is a schematic diagram of the transformer 3700 coupled to theelectrical circuit 3600 shown in FIG. 36 , in accordance with at leastone aspect of the present disclosure. The RF+/RF input terminals(primary winding) of the transformer 3700 are electrically coupled tothe RF Left/RF output terminals of the electrical circuit 3600. One sideof the secondary winding is coupled in series with first and secondblocking capacitors 3706, 3708. The second blocking capacitor is coupledto the second stage RF drive circuit 3774 a positive terminal. The otherside of the secondary winding is coupled to the second stage RF drivecircuit 3774 b negative terminal. The second stage RF drive circuit 3774a positive output is coupled to the ultrasonic blade and the secondstage RF drive circuit 3774 b negative ground terminal is coupled to anouter tube. In one aspect, a transformer has a turns-ratio of n₁:n₂ of1:50.

FIG. 38 is a schematic diagram of a circuit 3800 comprising separatepower sources for high power energy/drive circuits and low powercircuits, in accordance with at least one aspect of the presentdisclosure. A power supply 3812 includes a primary battery packcomprising first and second primary batteries 3815, 3817 (e.g., Li-ionbatteries) that are connected into the circuit 3800 by a switch 3818 anda secondary battery pack comprising a secondary battery 3820 that isconnected into the circuit by a switch 3823 when the power supply 3812is inserted into the battery assembly. The secondary battery 3820 is asag preventing battery that has componentry resistant to gamma or otherradiation sterilization. For instance, a switch mode power supply 3827and optional charge circuit within the battery assembly can beincorporated to allow the secondary battery 3820 to reduce the voltagesag of the primary batteries 3815, 3817. This guarantees full chargedcells at the beginning of a surgery that are easy to introduce into thesterile field. The primary batteries 3815, 3817 can be used to powermotor control circuits 3826 and energy circuits 3832 directly. The motorcontrol circuits 3826 are configured to control a motor, such as motor3829. The power supply/battery pack 3812 may comprise a dual typebattery assembly including primary Li-ion batteries 3815, 3817 andsecondary NiMH batteries 3820 with dedicated energy cells 3820 tocontrol handle electronics circuits 3830 from dedicated energy cells3815, 3817 to run the motor control circuits 3826 and the energycircuits 3832. In this case the circuit 3810 pulls from the secondarybatteries 3820 involved in driving the handle electronics circuits 3830when the primary batteries 3815, 3817 involved in driving the energycircuits 3832 and/or motor control circuits 3826 are dropping low. Inone various aspect, the circuit 3810 may include a one way diode thatwould not allow for current to flow in the opposite direction (e.g.,from the batteries involved in driving the energy and/or motor controlcircuits to the batteries involved in driving the electronics circuits).

Additionally, a gamma friendly charge circuit may be provided thatincludes a switch mode power supply 3827 using diodes and vacuum tubecomponents to minimize voltage sag at a predetermined level. With theinclusion of a minimum sag voltage that is a division of the NiMHvoltages (3 NiMH cells) the switch mode power supply 3827 could beeliminated. Additionally a modular system may be provided wherein theradiation hardened components are located in a module, making the modulesterilizable by radiation sterilization. Other non-radiation hardenedcomponents may be included in other modular components and connectionsmade between the modular components such that the componentry operatestogether as if the components were located together on the same circuitboard. If only two NiMH cells are desired the switch mode power supply3827 based on diodes and vacuum tubes allows for sterilizableelectronics within the disposable primary battery pack.

Turning now to FIG. 39 , there is shown a control circuit 3900 foroperating a battery 3901 powered RF generator circuit 3902 for use witha surgical instrument, in accordance with at least one aspect of thepresent disclosure. The surgical instrument is configured to use bothultrasonic vibration and high-frequency current to carry out surgicalcoagulation/cutting treatments on living tissue, and uses high-frequencycurrent to carry out a surgical coagulation treatment on living tissue.

FIG. 39 illustrates the control circuit 3900 that allows a dualgenerator system to switch between the RF generator circuit 3902 and theultrasonic generator circuit 3920 energy modalities for a surgicalinstrument of the surgical system 1000. In one aspect, a currentthreshold in an RF signal is detected. When the impedance of the tissueis low the high-frequency current through tissue is high when RF energyis used as the treatment source for the tissue. According to one aspect,a visual indicator 3912 or light located on the surgical instrument ofsurgical system 1000 may be configured to be in an on-state during thishigh current period. When the current falls below a threshold, thevisual indicator 3912 is in an off-state. Accordingly, a phototransistor3914 may be configured to detect the transition from an on-state to anoff-state and disengages the RF energy as shown in the control circuit3900 shown in FIG. 39 . Therefore, when the energy button is releasedand an energy switch 3926 is opened, the control circuit 3900 is resetand both the RF and ultrasonic generator circuits 3902, 3920 are heldoff.

With reference to FIG. 39 , in one aspect, a method of managing an RFgenerator circuit 3902 and ultrasound generator circuit 3920 isprovided. The RF generator circuit 3902 and/or the ultrasound generatorcircuit 3920 may be located in the handle assembly 1109, the ultrasonictransducer/RF generator assembly 1120, the battery assembly, the shaftassembly 1129, and/or the nozzle, of the multifunction electrosurgicalinstrument 1108, for example. The control circuit 3900 is held in areset state if the energy switch 3926 is off (e.g., open). Thus, whenthe energy switch 3926 is opened, the control circuit 3900 is reset andboth the RF and ultrasonic generator circuits 3902, 3920 are turned off.When the energy switch 3926 is squeezed and the energy switch 3926 isengaged (e.g., closed), RF energy is delivered to the tissue and thevisual indicator 3912 operated by a current sensing step-up transformer3904 will be lit while the tissue impedance is low. The light from thevisual indicator 3912 provides a logic signal to keep the ultrasonicgenerator circuit 3920 in the off state. Once the tissue impedanceincreases above a threshold and the high-frequency current through thetissue decreases below a threshold, the visual indicator 3912 turns offand the light transitions to an off-state. A logic signal generated bythis transition turns off a relay 3908, whereby the RF generator circuit3902 is turned off and the ultrasonic generator circuit 3920 is turnedon, to complete the coagulation and cut cycle.

Still with reference to FIG. 39 , in one aspect, the dual generatorcircuit configuration employs the on-board RF generator circuit 3902,which is battery 3901 powered, for one modality and a second, on-boardultrasound generator circuit 3920, which may be on-board in the handleassembly 1109, battery assembly, shaft assembly 1129, nozzle, and/or theultrasonic transducer/RF generator assembly 1120 of the multifunctionelectrosurgical instrument 1108, for example. The ultrasonic generatorcircuit 3920 also is battery 3901 operated. In various aspects, the RFgenerator circuit 3902 and the ultrasonic generator circuit 3920 may bean integrated or separable component of the handle assembly 1109.According to various aspects, having the dual RF/ultrasonic generatorcircuits 3902, 3920 as part of the handle assembly 1109 may eliminatethe need for complicated wiring. The RF/ultrasonic generator circuits3902, 3920 may be configured to provide the full capabilities of anexisting generator while utilizing the capabilities of a cordlessgenerator system simultaneously.

Either type of system can have separate controls for the modalities thatare not communicating with each other. The surgeon activates the RF andUltrasonic separately and at their discretion. Another approach would beto provide fully integrated communication schemes that share buttons,tissue status, instrument operating parameters (such as jaw closure,forces, etc.) and algorithms to manage tissue treatment. Variouscombinations of this integration can be implemented to provide theappropriate level of function and performance.

As discussed above, in one aspect, the control circuit 3900 includes thebattery 3901 powered RF generator circuit 3902 comprising a battery asan energy source. As shown, RF generator circuit 3902 is coupled to twoelectrically conductive surfaces referred to herein as electrodes 3906a, 3906 b (i.e., active electrode 3906 a and return electrode 3906 b)and is configured to drive the electrodes 3906 a, 3906 b with RF energy(e.g., high-frequency current). A first winding 3910 a of the step-uptransformer 3904 is connected in series with one pole of the bipolar RFgenerator circuit 3902 and the return electrode 3906 b. In one aspect,the first winding 3910 a and the return electrode 3906 b are connectedto the negative pole of the bipolar RF generator circuit 3902. The otherpole of the bipolar RF generator circuit 3902 is connected to the activeelectrode 3906 a through a switch contact 3909 of the relay 3908, or anysuitable electromagnetic switching device comprising an armature whichis moved by an electromagnet 3936 to operate the switch contact 3909.The switch contact 3909 is closed when the electromagnet 3936 isenergized and the switch contact 3909 is open when the electromagnet3936 is de-energized. When the switch contact is closed, RF currentflows through conductive tissue (not shown) located between theelectrodes 3906 a, 3906 b. It will be appreciated, that in one aspect,the active electrode 3906 a is connected to the positive pole of thebipolar RF generator circuit 3902.

A visual indicator circuit 3905 comprises the step-up transformer 3904,a series resistor R2, and the visual indicator 3912. The visualindicator 3912 can be adapted for use with the surgical instrument 1108and other electrosurgical systems and tools, such as those describedherein. The first winding 3910 a of the step-up transformer 3904 isconnected in series with the return electrode 3906 b and the secondwinding 3910 b of the step-up transformer 3904 is connected in serieswith the resistor R2 and the visual indicator 3912 comprising a typeNE-2 neon bulb, for example.

In operation, when the switch contact 3909 of the relay 3908 is open,the active electrode 3906 a is disconnected from the positive pole ofthe bipolar RF generator circuit 3902 and no current flows through thetissue, the return electrode 3906 b, and the first winding 3910 a of thestep-up transformer 3904. Accordingly, the visual indicator 3912 is notenergized and does not emit light. When the switch contact 3909 of therelay 3908 is closed, the active electrode 3906 a is connected to thepositive pole of the bipolar RF generator circuit 3902 enabling currentto flow through tissue, the return electrode 3906 b, and the firstwinding 3910 a of the step-up transformer 3904 to operate on tissue, forexample cut and cauterize the tissue.

A first current flows through the first winding 3910 a as a function ofthe impedance of the tissue located between the active and returnelectrodes 3906 a, 3906 b providing a first voltage across the firstwinding 3910 a of the step-up transformer 3904. A stepped up secondvoltage is induced across the second winding 3910 b of the step-uptransformer 3904. The secondary voltage appears across the resistor R2and energizes the visual indicator 3912 causing the neon bulb to lightwhen the current through the tissue is greater than a predeterminedthreshold. It will be appreciated that the circuit and component valuesare illustrative and not limited thereto. When the switch contact 3909of the relay 3908 is closed, current flows through the tissue and thevisual indicator 3912 is turned on.

Turning now to the energy switch 3926 portion of the control circuit3900, when the energy switch 3926 is open position, a logic high isapplied to the input of a first inverter 3928 and a logic low is appliedof one of the two inputs of the AND gate 3932. Thus, the output of theAND gate 3932 is low and a transistor 3934 is off to prevent currentfrom flowing through the winding of the electromagnet 3936. With theelectromagnet 3936 in the de-energized state, the switch contact 3909 ofthe relay 3908 remains open and prevents current from flowing throughthe electrodes 3906 a, 3906 b. The logic low output of the firstinverter 3928 also is applied to a second inverter 3930 causing theoutput to go high and resetting a flip-flop 3918 (e.g., a D-Typeflip-flop). At which time, the Q output goes low to turn off theultrasound generator circuit 3920 circuit and the Q output goes high andis applied to the other input of the AND gate 3932.

When the user presses the energy switch 3926 on the instrument handle toapply energy to the tissue between the electrodes 3906 a, 3906 b, theenergy switch 3926 closes and applies a logic low at the input of thefirst inverter 3928, which applies a logic high to other input of theAND gate 3932 causing the output of the AND gate 3932 to go high andturns on the transistor 3934. In the on state, the transistor 3934conducts and sinks current through the winding of the electromagnet 3936to energize the electromagnet 3936 and close the switch contact 3909 ofthe relay 3908. As discussed above, when the switch contact 3909 isclosed, current can flow through the electrodes 3906 a, 3906 b and thefirst winding 3910 a of the step-up transformer 3904 when tissue islocated between the electrodes 3906 a, 3906 b.

As discussed above, the magnitude of the current flowing through theelectrodes 3906 a, 3906 b depends on the impedance of the tissue locatedbetween the electrodes 3906 a, 3906 b. Initially, the tissue impedanceis low and the magnitude of the current high through the tissue and thefirst winding 3910 a. Consequently, the voltage impressed on the secondwinding 3910 b is high enough to turn on the visual indicator 3912. Thelight emitted by the visual indicator 3912 turns on the phototransistor3914, which pulls the input of an inverter 3916 low and causes theoutput of the inverter 3916 to go high. A high input applied to the CLKof the flip-flop 3918 has no effect on the Q or the Q outputs of theflip-flop 3918 and Q output remains low and the Q output remains high.Accordingly, while the visual indicator 3912 remains energized, theultrasound generator circuit 3920 is turned OFF and an ultrasonictransducer 3922 and an ultrasonic blade 3924 of the multifunctionelectrosurgical instrument are not activated.

As the tissue between the electrodes 3906 a, 3906 b dries up, due to theheat generated by the current flowing through the tissue, the impedanceof the tissue increases and the current therethrough decreases. When thecurrent through the first winding 3910 a decreases, the voltage acrossthe second winding 3910 b also decreases and when the voltage dropsbelow a minimum threshold required to operate the visual indicator 3912,the visual indicator 3912 and the phototransistor 3914 turn off. Whenthe phototransistor 3914 turns off, a logic high is applied to the inputof the inverter 3916 and a logic low is applied to the CLK input of theflip-flop 3918 to clock a logic high to the Q output and a logic low tothe Q output. The logic high at the Q output turns on the ultrasoundgenerator circuit 3920 to activate the ultrasonic transducer 3922 andthe ultrasonic blade 3924 to initiate cutting the tissue located betweenthe electrodes 3906 a, 3906 a. Simultaneously or near simultaneouslywith the ultrasound generator circuit 3920 turning on, the Q output ofthe flip-flop 3918 goes low and causes the output of the AND gate 3932to go low and turn off the transistor 3934, thereby de-energizing theelectromagnet 3936 and opening the switch contact 3909 of the relay 3908to cut off the flow of current through the electrodes 3906 a, 3906 b.

While the switch contact 3909 of the relay 3908 is open, no currentflows through the electrodes 3906 a, 3906 b, tissue, and the firstwinding 3910 a of the step-up transformer 3904. Therefore, no voltage isdeveloped across the second winding 3910 b and no current flows throughthe visual indicator 3912.

The state of the Q and the Q outputs of the flip-flop 3918 remain thesame while the user squeezes the energy switch 3926 on the instrumenthandle to maintain the energy switch 3926 closed. Thus, the ultrasonicblade 3924 remains activated and continues cutting the tissue betweenthe jaws of the end effector while no current flows through theelectrodes 3906 a, 3906 b from the bipolar RF generator circuit 3902.When the user releases the energy switch 3926 on the instrument handle,the energy switch 3926 opens and the output of the first inverter 3928goes low and the output of the second inverter 3930 goes high to resetthe flip-flop 3918 causing the Q output to go low and turn off theultrasound generator circuit 3920. At the same time, the Q output goeshigh and the circuit is now in an off state and ready for the user toactuate the energy switch 3926 on the instrument handle to close theenergy switch 3926, apply current to the tissue located between theelectrodes 3906 a, 3906 b, and repeat the cycle of applying RF energy tothe tissue and ultrasonic energy to the tissue as described above.

FIG. 40 illustrates a diagram of a surgical system 4000, whichrepresents one aspect of the surgical system 1000, comprising a feedbacksystem for use with any one of the surgical instruments of surgicalsystem 1000, which may include or implement many of the featuresdescribed herein. The surgical system 4000 may include a generator 4002coupled to a surgical instrument that includes an end effector 4006,which may be activated when a clinician operates a trigger 4010. Invarious aspects, the end effector 4006 may include an ultrasonic bladeto deliver ultrasonic vibration to carry out surgicalcoagulation/cutting treatments on living tissue. In other aspects theend effector 4006 may include electrically conductive elements coupledto an electrosurgical high-frequency current energy source to carry outsurgical coagulation or cauterization treatments on living tissue andeither a mechanical knife with a sharp edge or an ultrasonic blade tocarry out cutting treatments on living tissue. When the trigger 4010 isactuated, a force sensor 4012 may generate a signal indicating theamount of force being applied to the trigger 4010. In addition to, orinstead of a force sensor 4012, the surgical instrument may include aposition sensor 4013, which may generate a signal indicating theposition of the trigger 4010 (e.g., how far the trigger has beendepressed or otherwise actuated). In one aspect, the position sensor4013 may be a sensor positioned with an outer tubular sheath orreciprocating tubular actuating member located within the outer tubularsheath of the surgical instrument. In one aspect, the sensor may be aHall-effect sensor or any suitable transducer that varies its outputvoltage in response to a magnetic field. The Hall-effect sensor may beused for proximity switching, positioning, speed detection, and currentsensing applications. In one aspect, the Hall-effect sensor operates asan analog transducer, directly returning a voltage. With a knownmagnetic field, its distance from the Hall plate can be determined.

A control circuit 4008 may receive the signals from the sensors 4012and/or 4013. The control circuit 4008 may include any suitable analog ordigital circuit components. The control circuit 4008 also maycommunicate with the generator 4002 and/or a transducer 4004 to modulatethe power delivered to the end effector 4006 and/or the generator levelor ultrasonic blade amplitude of the end effector 4006 based on theforce applied to the trigger 4010 and/or the position of the trigger4010 and/or the position of the outer tubular sheath described aboverelative to a reciprocating tubular actuating member located within anouter tubular sheath (e.g., as measured by a Hall-effect sensor andmagnet combination). For example, as more force is applied to thetrigger 4010, more power and/or higher ultrasonic blade amplitude may bedelivered to the end effector 4006. According to various aspects, theforce sensor 4012 may be replaced by a multi-position switch.

According to various aspects, the end effector 4006 may include a clampor clamping mechanism. When the trigger 4010 is initially actuated, theclamping mechanism may close, clamping tissue between a clamp arm andthe end effector 4006. As the force applied to the trigger increases(e.g., as sensed by force sensor 4012) the control circuit 4008 mayincrease the power delivered to the end effector 4006 by the transducer4004 and/or the generator level or ultrasonic blade amplitude broughtabout in the end effector 4006. In one aspect, trigger position, assensed by position sensor 4013 or clamp or clamp arm position, as sensedby position sensor 4013 (e.g., with a Hall-effect sensor), may be usedby the control circuit 4008 to set the power and/or amplitude of the endeffector 4006. For example, as the trigger is moved further towards afully actuated position, or the clamp or clamp arm moves further towardsthe ultrasonic blade (or end effector 4006), the power and/or amplitudeof the end effector 4006 may be increased.

According to various aspects, the surgical instrument of the surgicalsystem 4000 also may include one or more feedback devices for indicatingthe amount of power delivered to the end effector 4006. For example, aspeaker 4014 may emit a signal indicative of the end effector power.According to various aspects, the speaker 4014 may emit a series ofpulse sounds, where the frequency of the sounds indicates power. Inaddition to, or instead of the speaker 4014, the surgical instrument mayinclude a visual display 4016. The visual display 4016 may indicate endeffector power according to any suitable method. For example, the visualdisplay 4016 may include a series of LEDs, where end effector power isindicated by the number of illuminated LEDs. The speaker 4014 and/orvisual display 4016 may be driven by the control circuit 4008. Accordingto various aspects, the surgical instrument may include a ratchetingdevice connected to the trigger 4010. The ratcheting device may generatean audible sound as more force is applied to the trigger 4010, providingan indirect indication of end effector power. The surgical instrumentmay include other features that may enhance safety. For example, thecontrol circuit 4008 may be configured to prevent power from beingdelivered to the end effector 4006 in excess of a predeterminedthreshold. Also, the control circuit 4008 may implement a delay betweenthe time when a change in end effector power is indicated (e.g., byspeaker 4014 or visual display 4016), and the time when the change inend effector power is delivered. In this way, a clinician may have amplewarning that the level of ultrasonic power that is to be delivered tothe end effector 4006 is about to change.

In one aspect, the ultrasonic or high-frequency current generators ofthe surgical system 1000 may be configured to generate the electricalsignal waveform digitally such that the desired using a predeterminednumber of phase points stored in a lookup table to digitize the waveshape. The phase points may be stored in a table defined in a memory, afield programmable gate array (FPGA), or any suitable non-volatilememory. FIG. 41 illustrates one aspect of a fundamental architecture fora digital synthesis circuit such as a direct digital synthesis (DDS)circuit 4100 configured to generate a plurality of wave shapes for theelectrical signal waveform. The generator software and digital controlsmay command the FPGA to scan the addresses in the lookup table 4104which in turn provides varying digital input values to a DAC circuit4108 that feeds a power amplifier. The addresses may be scannedaccording to a frequency of interest. Using such a lookup table 4104enables generating various types of wave shapes that can be fed intotissue or into a transducer, an RF electrode, multiple transducerssimultaneously, multiple RF electrodes simultaneously, or a combinationof RF and ultrasonic instruments. Furthermore, multiple lookup tables4104 that represent multiple wave shapes can be created, stored, andapplied to tissue from a generator.

The waveform signal may be configured to control at least one of anoutput current, an output voltage, or an output power of an ultrasonictransducer and/or an RF electrode, or multiples thereof (e.g. two ormore ultrasonic transducers and/or two or more RF electrodes). Further,where the surgical instrument comprises an ultrasonic components, thewaveform signal may be configured to drive at least two vibration modesof an ultrasonic transducer of the at least one surgical instrument.Accordingly, a generator may be configured to provide a waveform signalto at least one surgical instrument wherein the waveform signalcorresponds to at least one wave shape of a plurality of wave shapes ina table. Further, the waveform signal provided to the two surgicalinstruments may comprise two or more wave shapes. The table may compriseinformation associated with a plurality of wave shapes and the table maybe stored within the generator. In one aspect or example, the table maybe a direct digital synthesis table, which may be stored in an FPGA ofthe generator. The table may be addressed by anyway that is convenientfor categorizing wave shapes. According to one aspect, the table, whichmay be a direct digital synthesis table, is addressed according to afrequency of the waveform signal. Additionally, the informationassociated with the plurality of wave shapes may be stored as digitalinformation in the table.

The analog electrical signal waveform may be configured to control atleast one of an output current, an output voltage, or an output power ofan ultrasonic transducer and/or an RF electrode, or multiples thereof(e.g., two or more ultrasonic transducers and/or two or more RFelectrodes). Further, where the surgical instrument comprises ultrasoniccomponents, the analog electrical signal waveform may be configured todrive at least two vibration modes of an ultrasonic transducer of the atleast one surgical instrument. Accordingly, the generator circuit may beconfigured to provide an analog electrical signal waveform to at leastone surgical instrument wherein the analog electrical signal waveformcorresponds to at least one wave shape of a plurality of wave shapesstored in a lookup table 4104. Further, the analog electrical signalwaveform provided to the two surgical instruments may comprise two ormore wave shapes. The lookup table 4104 may comprise informationassociated with a plurality of wave shapes and the lookup table 4104 maybe stored either within the generator circuit or the surgicalinstrument. In one aspect or example, the lookup table 4104 may be adirect digital synthesis table, which may be stored in an FPGA of thegenerator circuit or the surgical instrument. The lookup table 4104 maybe addressed by anyway that is convenient for categorizing wave shapes.According to one aspect, the lookup table 4104, which may be a directdigital synthesis table, is addressed according to a frequency of thedesired analog electrical signal waveform. Additionally, the informationassociated with the plurality of wave shapes may be stored as digitalinformation in the lookup table 4104.

With the widespread use of digital techniques in instrumentation andcommunications systems, a digitally-controlled method of generatingmultiple frequencies from a reference frequency source has evolved andis referred to as direct digital synthesis. The basic architecture isshown in FIG. 41 . In this simplified block diagram, a DDS circuit iscoupled to a processor, controller, or a logic device of the generatorcircuit and to a memory circuit located in the generator circuit of thesurgical system 1000. The DDS circuit 4100 comprises an address counter4102, lookup table 4104, a register 4106, a DAC circuit 4108, and afilter 4112. A stable clock f_(c) is received by the address counter4102 and the register 4106 drives a programmable-read-only-memory (PROM)which stores one or more integral number of cycles of a sinewave (orother arbitrary waveform) in a lookup table 4104. As the address counter4102 steps through memory locations, values stored in the lookup table4104 are written to the register 4106, which is coupled to the DACcircuit 4108. The corresponding digital amplitude of the signal at thememory location of the lookup table 4104 drives the DAC circuit 4108,which in turn generates an analog output signal 4110. The spectralpurity of the analog output signal 4110 is determined primarily by theDAC circuit 4108. The phase noise is basically that of the referenceclock f_(out). The first analog output signal 4110 output from the DACcircuit 4108 is filtered by the filter 4112 and a second analog outputsignal 4114 output by the filter 4112 is provided to an amplifier havingan output coupled to the output of the generator circuit. The secondanalog output signal has a frequency f_(out).

Because the DDS circuit 4100 is a sampled data system, issues involvedin sampling must be considered: quantization noise, aliasing, filtering,etc. For instance, the higher order harmonics of the DAC circuit 4108output frequencies fold back into the Nyquist bandwidth, making themunfilterable, whereas, the higher order harmonics of the output ofphase-locked-loop (PLL) based synthesizers can be filtered. The lookuptable 4104 contains signal data for an integral number of cycles. Thefinal output frequency fa can be changed changing the reference clockfrequency f_(out) or by reprogramming the PROM.

The DDS circuit 4100 may comprise multiple lookup tables 4104 where thelookup table 4104 stores a waveform represented by a predeterminednumber of samples, wherein the samples define a predetermined shape ofthe waveform. Thus multiple waveforms having a unique shape can bestored in multiple lookup tables 4104 to provide different tissuetreatments based on instrument settings or tissue feedback. Examples ofwaveforms include high crest factor RF electrical signal waveforms forsurface tissue coagulation, low crest factor RF electrical signalwaveform for deeper tissue penetration, and electrical signal waveformsthat promote efficient touch-up coagulation. In one aspect, the DDScircuit 4100 can create multiple wave shape lookup tables 4104 andduring a tissue treatment procedure (e.g., “on-the-fly” or in virtualreal time based on user or sensor inputs) switch between different waveshapes stored in separate lookup tables 4104 based on the tissue effectdesired and/or tissue feedback.

Accordingly, switching between wave shapes can be based on tissueimpedance and other factors, for example. In other aspects, the lookuptables 4104 can store electrical signal waveforms shaped to maximize thepower delivered into the tissue per cycle (i.e., trapezoidal or squarewave). In other aspects, the lookup tables 4104 can store wave shapessynchronized in such way that they make maximizing power delivery by themultifunction surgical instrument of surgical system 1000 whiledelivering RF and ultrasonic drive signals. In yet other aspects, thelookup tables 4104 can store electrical signal waveforms to driveultrasonic and RF therapeutic, and/or sub-therapeutic, energysimultaneously while maintaining ultrasonic frequency lock. Custom waveshapes specific to different instruments and their tissue effects can bestored in the non-volatile memory of the generator circuit or in thenon-volatile memory (e.g., EEPROM) of the surgical system 1000 and befetched upon connecting the multifunction surgical instrument to thegenerator circuit. An example of an exponentially damped sinusoid, asused in many high crest factor “coagulation” waveforms is shown in FIG.43 .

A more flexible and efficient implementation of the DDS circuit 4100employs a digital circuit called a Numerically Controlled Oscillator(NCO). A block diagram of a more flexible and efficient digitalsynthesis circuit such as a DDS circuit 4200 is shown in FIG. 42 . Inthis simplified block diagram, a DDS circuit 4200 is coupled to aprocessor, controller, or a logic device of the generator and to amemory circuit located either in the generator or in any of the surgicalinstruments of surgical system 1000. The DDS circuit 4200 comprises aload register 4202, a parallel delta phase register 4204, an addercircuit 4216, a phase register 4208, a lookup table 4210(phase-to-amplitude converter), a DAC circuit 4212, and a filter 4214.The adder circuit 4216 and the phase register 4208 form part of a phaseaccumulator 4206. A clock frequency f_(c) is applied to the phaseregister 4208 and a DAC circuit 4212. The load register 4202 receives atuning word that specifies output frequency as a fraction of thereference clock frequency signal f_(c). The output of the load register4202 is provided to the parallel delta phase register 4204 with a tuningword M.

The DDS circuit 4200 includes a sample clock that generates the clockfrequency f_(c), the phase accumulator 4206, and the lookup table 4210(e.g., phase to amplitude converter). The content of the phaseaccumulator 4206 is updated once per clock cycle f_(c). When time thephase accumulator 4206 is updated, the digital number, M, stored in theparallel delta phase register 4204 is added to the number in the phaseregister 4208 by the adder circuit 4216. Assuming that the number in theparallel delta phase register 4204 is 00 . . . 01 and that the initialcontents of the phase accumulator 4206 is 00 . . . 00. The phaseaccumulator 4206 is updated by 00 . . . 01 per clock cycle. If the phaseaccumulator 4206 is 32-bits wide, 232 clock cycles (over 4 billion) arerequired before the phase accumulator 4206 returns to 00 . . . 00, andthe cycle repeats.

A truncated output 4218 of the phase accumulator 4206 is provided to aphase-to amplitude converter lookup table 4210 and the output of thelookup table 4210 is coupled to a DAC circuit 4212. The truncated output4218 of the phase accumulator 4206 serves as the address to a sine (orcosine) lookup table. An address in the lookup table corresponds to aphase point on the sinewave from 0° to 360°. The lookup table 4210contains the corresponding digital amplitude information for onecomplete cycle of a sinewave. The lookup table 4210 therefore maps thephase information from the phase accumulator 4206 into a digitalamplitude word, which in turn drives the DAC circuit 4212. The output ofthe DAC circuit is a first analog signal 4220 and is filtered by afilter 4214. The output of the filter 4214 is a second analog signal4222, which is provided to a power amplifier coupled to the output ofthe generator circuit.

In one aspect, the electrical signal waveform may be digitized into 1024(210) phase points, although the wave shape may be digitized is anysuitable number of 2n phase points ranging from 256 (28) to 281, 474,976, 710, 656 (248), where n is a positive integer, as shown in TABLE 1.The electrical signal waveform may be expressed as A_(n)(θ_(n)), where anormalized amplitude A_(n) at a point n is represented by a phase angleθ_(n) is referred to as a phase point at point n. The number of discretephase points n determines the tuning resolution of the DDS circuit 4200(as well as the DDS circuit 4100 shown in FIG. 41 ).

TABLE 1 specifies the electrical signal waveform digitized into a numberof phase points.

TABLE 1 N Number of Phase Points 2^(n) 8 256 10 1,024 12 4,096 14 16,38416 65,536 18 262,144 20 1,048,576 22 4,194,304 24 16,777,216 2667,108,864 28 268,435,456 . . . . . . 32 4,294,967,296 . . . . . . 48281,474,976,710,656 . . . . . .

The generator circuit algorithms and digital control circuits scan theaddresses in the lookup table 4210, which in turn provides varyingdigital input values to the DAC circuit 4212 that feeds the filter 4214and the power amplifier. The addresses may be scanned according to afrequency of interest. Using the lookup table enables generating varioustypes of shapes that can be converted into an analog output signal bythe DAC circuit 4212, filtered by the filter 4214, amplified by thepower amplifier coupled to the output of the generator circuit, and fedto the tissue in the form of RF energy or fed to an ultrasonictransducer and applied to the tissue in the form of ultrasonicvibrations which deliver energy to the tissue in the form of heat. Theoutput of the amplifier can be applied to an RF electrode, multiple RFelectrodes simultaneously, an ultrasonic transducer, multiple ultrasonictransducers simultaneously, or a combination of RF and ultrasonictransducers, for example. Furthermore, multiple wave shape tables can becreated, stored, and applied to tissue from a generator circuit.

With reference back to FIG. 41 , for n=32, and M=1, the phaseaccumulator 4206 steps through 232 possible outputs before it overflowsand restarts. The corresponding output wave frequency is equal to theinput clock frequency divided by 232. If M=2, then the phase register1708 “rolls over” twice as fast, and the output frequency is doubled.This can be generalized as follows.

For a phase accumulator 4206 configured to accumulate n-bits (ngenerally ranges from 24 to 32 in most DDS systems, but as previouslydiscussed n may be selected from a wide range of options), there are2^(n) possible phase points. The digital word in the delta phaseregister, M, represents the amount the phase accumulator is incrementedper clock cycle. If f_(c) is the clock frequency, then the frequency ofthe output sinewave is equal to:

$f_{0} = \frac{M \cdot f_{c}}{2^{n}}$

The above equation is known as the DDS “tuning equation.” Note that thefrequency resolution of the system is equal to

$\frac{f_{0}}{2^{n}}.$

For n=32, the resolution is greater than one part in four billion. Inone aspect of the DDS circuit 4200, not all of the bits out of the phaseaccumulator 4206 are passed on to the lookup table 4210, but aretruncated, leaving only the first 13 to 15 most significant bits (MSBs),for example. This reduces the size of the lookup table 4210 and does notaffect the frequency resolution. The phase truncation only adds a smallbut acceptable amount of phase noise to the final output.

The electrical signal waveform may be characterized by a current,voltage, or power at a predetermined frequency. Further, where any oneof the surgical instruments of surgical system 1000 comprises ultrasoniccomponents, the electrical signal waveform may be configured to drive atleast two vibration modes of an ultrasonic transducer of the at leastone surgical instrument. Accordingly, the generator circuit may beconfigured to provide an electrical signal waveform to at least onesurgical instrument wherein the electrical signal waveform ischaracterized by a predetermined wave shape stored in the lookup table4210 (or lookup table 4104 FIG. 41 ). Further, the electrical signalwaveform may be a combination of two or more wave shapes. The lookuptable 4210 may comprise information associated with a plurality of waveshapes. In one aspect or example, the lookup table 4210 may be generatedby the DDS circuit 4200 and may be referred to as a direct digitalsynthesis table. DDS works by first storing a large repetitive waveformin onboard memory. A cycle of a waveform (sine, triangle, square,arbitrary) can be represented by a predetermined number of phase pointsas shown in TABLE 1 and stored into memory. Once the waveform is storedinto memory, it can be generated at very precise frequencies. The directdigital synthesis table may be stored in a non-volatile memory of thegenerator circuit and/or may be implemented with a FPGA circuit in thegenerator circuit. The lookup table 4210 may be addressed by anysuitable technique that is convenient for categorizing wave shapes.According to one aspect, the lookup table 4210 is addressed according toa frequency of the electrical signal waveform. Additionally, theinformation associated with the plurality of wave shapes may be storedas digital information in a memory or as part of the lookup table 4210.

In one aspect, the generator circuit may be configured to provideelectrical signal waveforms to at least two surgical instrumentssimultaneously. The generator circuit also may be configured to providethe electrical signal waveform, which may be characterized two or morewave shapes, via an output channel of the generator circuit to the twosurgical instruments simultaneously. For example, in one aspect theelectrical signal waveform comprises a first electrical signal to drivean ultrasonic transducer (e.g., ultrasonic drive signal), a second RFdrive signal, and/or a combination thereof. In addition, an electricalsignal waveform may comprise a plurality of ultrasonic drive signals, aplurality of RF drive signals, and/or a combination of a plurality ofultrasonic and RF drive signals.

In addition, a method of operating the generator circuit according tothe present disclosure comprises generating an electrical signalwaveform and providing the generated electrical signal waveform to anyone of the surgical instruments of surgical system 1000, wheregenerating the electrical signal waveform comprises receivinginformation associated with the electrical signal waveform from amemory. The generated electrical signal waveform comprises at least onewave shape. Furthermore, providing the generated electrical signalwaveform to the at least one surgical instrument comprises providing theelectrical signal waveform to at least two surgical instrumentssimultaneously.

The generator circuit as described herein may allow for the generationof various types of direct digital synthesis tables. Examples of waveshapes for RF/Electrosurgery signals suitable for treating a variety oftissue generated by the generator circuit include RF signals with a highcrest factor (which may be used for surface coagulation in RF mode), alow crest factor RF signals (which may be used for deeper tissuepenetration), and waveforms that promote efficient touch-up coagulation.The generator circuit also may generate multiple wave shapes employing adirect digital synthesis lookup table 4210 and, on the fly, can switchbetween particular wave shapes based on the desired tissue effect.Switching may be based on tissue impedance and/or other factors.

In addition to traditional sine/cosine wave shapes, the generatorcircuit may be configured to generate wave shape(s) that maximize thepower into tissue per cycle (i.e., trapezoidal or square wave). Thegenerator circuit may provide wave shape(s) that are synchronized tomaximize the power delivered to the load when driving RF and ultrasonicsignals simultaneously and to maintain ultrasonic frequency lock,provided that the generator circuit includes a circuit topology thatenables simultaneously driving RF and ultrasonic signals. Further,custom wave shapes specific to instruments and their tissue effects canbe stored in a non-volatile memory (NVM) or an instrument EEPROM and canbe fetched upon connecting any one of the surgical instruments ofsurgical system 1000 to the generator circuit.

The DDS circuit 4200 may comprise multiple lookup tables 4104 where thelookup table 4210 stores a waveform represented by a predeterminednumber of phase points (also may be referred to as samples), wherein thephase points define a predetermined shape of the waveform. Thus multiplewaveforms having a unique shape can be stored in multiple lookup tables4210 to provide different tissue treatments based on instrument settingsor tissue feedback. Examples of waveforms include high crest factor RFelectrical signal waveforms for surface tissue coagulation, low crestfactor RF electrical signal waveform for deeper tissue penetration, andelectrical signal waveforms that promote efficient touch-up coagulation.In one aspect, the DDS circuit 4200 can create multiple wave shapelookup tables 4210 and during a tissue treatment procedure (e.g.,“on-the-fly” or in virtual real time based on user or sensor inputs)switch between different wave shapes stored in different lookup tables4210 based on the tissue effect desired and/or tissue feedback.

Accordingly, switching between wave shapes can be based on tissueimpedance and other factors, for example. In other aspects, the lookuptables 4210 can store electrical signal waveforms shaped to maximize thepower delivered into the tissue per cycle (i.e., trapezoidal or squarewave). In other aspects, the lookup tables 4210 can store wave shapessynchronized in such way that they make maximizing power delivery by anyone of the surgical instruments of surgical system 1000 when deliveringRF and ultrasonic drive signals. In yet other aspects, the lookup tables4210 can store electrical signal waveforms to drive ultrasonic and RFtherapeutic, and/or sub-therapeutic, energy simultaneously whilemaintaining ultrasonic frequency lock. Generally, the output wave shapemay be in the form of a sine wave, cosine wave, pulse wave, square wave,and the like. Nevertheless, the more complex and custom wave shapesspecific to different instruments and their tissue effects can be storedin the non-volatile memory of the generator circuit or in thenon-volatile memory (e.g., EEPROM) of the surgical instrument and befetched upon connecting the surgical instrument to the generatorcircuit. One example of a custom wave shape is an exponentially dampedsinusoid as used in many high crest factor “coagulation” waveforms, asshown in FIG. 43 .

FIG. 43 illustrates one cycle of a discrete time digital electricalsignal waveform 4300, in accordance with at least one aspect of thepresent disclosure of an analog waveform 4304 (shown superimposed overthe discrete time digital electrical signal waveform 4300 for comparisonpurposes). The horizontal axis represents Time (t) and the vertical axisrepresents digital phase points. The digital electrical signal waveform4300 is a digital discrete time version of the desired analog waveform4304, for example. The digital electrical signal waveform 4300 isgenerated by storing an amplitude phase point 4302 that represents theamplitude per clock cycle T_(clk) over one cycle or period T_(o). Thedigital electrical signal waveform 4300 is generated over one periodT_(o) by any suitable digital processing circuit. The amplitude phasepoints are digital words stored in a memory circuit. In the exampleillustrated in FIGS. 41, 42 , the digital word is a six-bit word that iscapable of storing the amplitude phase points with a resolution of 26 or64 bits. It will be appreciated that the examples shown in FIGS. 41, 42is for illustrative purposes and in actual implementations theresolution can be much higher. The digital amplitude phase points 4302over one cycle T_(o) are stored in the memory as a string of stringwords in a lookup table 4104, 4210 as described in connection with FIGS.41, 42 , for example. To generate the analog version of the analogwaveform 4304, the amplitude phase points 4302 are read sequentiallyfrom the memory from 0 to T_(o) per clock cycle T_(clk) and areconverted by a DAC circuit 4108, 4212, also described in connection withFIGS. 41, 42 . Additional cycles can be generated by repeatedly readingthe amplitude phase points 4302 of the digital electrical signalwaveform 4300 the from 0 to T_(o) for as many cycles or periods as maybe desired. The smooth analog version of the analog waveform 4304 isachieved by filtering the output of the DAC circuit 4108, 4212 by afilter 4112, 4214 (FIGS. 41 and 42 ). The filtered analog output signal4114, 4222 (FIGS. 41 and 42 ) is applied to the input of a poweramplifier.

FIG. 44 is a diagram of a control system 12950 configured to provideprogressive closure of a closure member (e.g., closure tube) when thedisplacement member advances distally and couples into a clamp arm(e.g., anvil) to lower the closure force load on the closure member at adesired rate and decrease the firing force load on the firing memberaccording to one aspect of this disclosure. In one aspect, the controlsystem 12950 may be implemented as a nested PID feedback controller. APID controller is a control loop feedback mechanism (controller) tocontinuously calculate an error value as the difference between adesired set point and a measured process variable and applies acorrection based on proportional, integral, and derivative terms(sometimes denoted P, I, and D respectively). The nested PID controllerfeedback control system 12950 includes a primary controller 12952, in aprimary (outer) feedback loop 12954 and a secondary controller 12955 ina secondary (inner) feedback loop 12956. The primary controller 12952may be a PID controller 12972 as shown in FIG. 45 , and the secondarycontroller 12955 also may be a PID controller 12972 as shown in FIG. 45. The primary controller 12952 controls a primary process 12958 and thesecondary controller 12955 controls a secondary process 12960. Theoutput 12966 of the primary process 12958 is subtracted from a primaryset point SP₁ by a first summer 12962. The first summer 12962 produces asingle sum output signal which is applied to the primary controller12952. The output of the primary controller 12952 is the secondary setpoint SP₂. The output 12968 of the secondary process 12960 is subtractedfrom the secondary set point SP₂ by a second summer 12964.

In the context of controlling the displacement of a closure tube, thecontrol system 12950 may be configured such that the primary set pointSP₁ is a desired closure force value and the primary controller 12952 isconfigured to receive the closure force from a torque sensor coupled tothe output of a closure motor and determine a set point SP₂ motorvelocity for the closure motor. In other aspects, the closure force maybe measured with strain gauges, load cells, or other suitable forcesensors. The closure motor velocity set point SP₂ is compared to theactual velocity of the closure tube, which is determined by thesecondary controller 12955. The actual velocity of the closure tube maybe measured by comparing measuring the displacement of the closure tubewith the position sensor and measuring elapsed time with atimer/counter. Other techniques, such as linear or rotary encoders maybe employed to measure displacement of the closure tube. The output12968 of the secondary process 12960 is the actual velocity of theclosure tube. This closure tube velocity output 12968 is provided to theprimary process 12958 which determines the force acting on the closuretube and is fed back to the adder 12962, which subtracts the measuredclosure force from the primary set point SP₁. The primary set point SP₁may be an upper threshold or a lower threshold. Based on the output ofthe adder 12962, the primary controller 12952 controls the velocity anddirection of the closure motor. The secondary controller 12955 controlsthe velocity of the closure motor based on the actual velocity ofclosure tube measured by the secondary process 12960 and the secondaryset point SP₂, which is based on a comparison of the actual firing forceand the firing force upper and lower thresholds.

FIG. 45 illustrates a PID feedback control system 12970 according to oneaspect of this disclosure. The primary controller 12952 or the secondarycontroller 12955, or both, may be implemented as a PID controller 12972.In one aspect, the PID controller 12972 may comprise a proportionalelement 12974 (P), an integral element 12976 (I), and a derivativeelement 12978 (D). The outputs of the P, I, D elements 12974, 12976,12978 are summed by a summer 12986, which provides the control variableμ(t) to the process 12980. The output of the process 12980 is theprocess variable y(t). A summer 12984 calculates the difference betweena desired set point r(t) and a measured process variable y(t). The PIDcontroller 12972 continuously calculates an error value e(t) (e.g.,difference between closure force threshold and measured closure force)as the difference between a desired set point r(t) (e.g., closure forcethreshold) and a measured process variable y(t) (e.g., velocity anddirection of closure tube) and applies a correction based on theproportional, integral, and derivative terms calculated by theproportional element 12974 (P), integral element 12976 (I), andderivative element 12978 (D), respectively. The PID controller 12972attempts to minimize the error e(t) over time by adjustment of thecontrol variable μ(t) (e.g., velocity and direction of the closuretube).

In accordance with the PID algorithm, the “P” element 12974 accounts forpresent values of the error. For example, if the error is large andpositive, the control output will also be large and positive. Inaccordance with the present disclosure, the error term e(t) is thedifferent between the desired closure force and the measured closureforce of the closure tube. The “I” element 12976 accounts for pastvalues of the error. For example, if the current output is notsufficiently strong, the integral of the error will accumulate overtime, and the controller will respond by applying a stronger action. The“D” element 12978 accounts for possible future trends of the error,based on its current rate of change. For example, continuing the Pexample above, when the large positive control output succeeds inbringing the error closer to zero, it also puts the process on a path tolarge negative error in the near future. In this case, the derivativeturns negative and the D module reduces the strength of the action toprevent this overshoot.

It will be appreciated that other variables and set points may bemonitored and controlled in accordance with the feedback control systems12950, 12970. For example, the adaptive closure member velocity controlalgorithm described herein may measure at least two of the followingparameters: firing member stroke location, firing member load,displacement of cutting element, velocity of cutting element, closuretube stroke location, closure tube load, among others.

Ultrasonic surgical devices, such as ultrasonic scalpels, are findingincreasingly widespread applications in surgical procedures by virtue oftheir unique performance characteristics. Depending upon specific deviceconfigurations and operational parameters, ultrasonic surgical devicescan provide substantially simultaneous transection of tissue andhomeostasis by coagulation, desirably minimizing patient trauma. Anultrasonic surgical device may comprise a handpiece containing anultrasonic transducer, and an instrument coupled to the ultrasonictransducer having a distally-mounted end effector (e.g., a blade tip) tocut and seal tissue. In some cases, the instrument may be permanentlyaffixed to the handpiece. In other cases, the instrument may bedetachable from the handpiece, as in the case of a disposable instrumentor an interchangeable instrument. The end effector transmits ultrasonicenergy to tissue brought into contact with the end effector to realizecutting and sealing action. Ultrasonic surgical devices of this naturecan be configured for open surgical use, laparoscopic, or endoscopicsurgical procedures including robotic-assisted procedures.

Ultrasonic energy cuts and coagulates tissue using temperatures lowerthan those used in electrosurgical procedures and can be transmitted tothe end effector by an ultrasonic generator in communication with thehandpiece. Vibrating at high frequencies (e.g., 55,500 cycles persecond), the ultrasonic blade denatures protein in the tissue to form asticky coagulum. Pressure exerted on tissue by the blade surfacecollapses blood vessels and allows the coagulum to form a hemostaticseal. A surgeon can control the cutting speed and coagulation by theforce applied to the tissue by the end effector, the time over which theforce is applied, and the selected excursion level of the end effector.

The ultrasonic transducer may be modeled as an equivalent circuitcomprising a first branch laving a static capacitance and a second“motional” branch having a serially connected inductance, resistance andcapacitance that define the electromechanical properties of a resonator.Known ultrasonic generators may include a tuning inductor for tuning outthe static capacitance at a resonant frequency so that substantially allof a generator's drive signal current flows into the motional branch.Accordingly, by using a tuning inductor, the generator's drive signalcurrent represents the motional branch current, and the generator isthus able to control its drive signal to maintain the ultrasonictransducer's resonant frequency. The tuning inductor may also transformthe phase impedance plot of the ultrasonic transducer to improve thegenerator's frequency lock capabilities. However, the tuning inductormust be matched with the specific static capacitance of an ultrasonictransducer at the operational resonant frequency. In other words, adifferent ultrasonic transducer having a different static capacitancerequires a different tuning inductor.

Additionally, in some ultrasonic generator architectures, thegenerator's drive signal exhibits asymmetrical harmonic distortion thatcomplicates impedance magnitude and phase measurements. For example, theaccuracy of impedance phase measurements may be reduced due to harmonicdistortion in the current and voltage signals.

Moreover, electromagnetic interference in noisy environments decreasesthe ability of the generator to maintain lock on the ultrasonictransducer's resonant frequency, increasing the likelihood of invalidcontrol algorithm inputs.

Electrosurgical devices for applying electrical energy to tissue inorder to treat and/or destroy the tissue are also finding increasinglywidespread applications in surgical procedures. An electrosurgicaldevice may comprise a handpiece and an instrument having adistally-mounted end effector (e.g., one or more electrodes). The endeffector can be positioned against the tissue such that electricalcurrent is introduced into the tissue. Electrosurgical devices can beconfigured for bipolar or monopolar operation. During bipolar operation,current is introduced into and returned from the tissue by active andreturn electrodes, respectively, of the end effector. During monopolaroperation, current is introduced into the tissue by an active electrodeof the end effector and returned through a return electrode (e.g., agrounding pad) separately located on a patient's body. Heat generated bythe current flowing through the tissue may form hemostatic seals withinthe tissue and/or between tissues and thus may be particularly usefulfor sealing blood vessels, for example. The end effector of anelectrosurgical device may also comprise a cutting member that ismovable relative to the tissue and the electrodes to transect thetissue.

Electrical energy applied by an electrosurgical device can betransmitted to the instrument by a generator in communication with thehandpiece. The electrical energy may be in the form of radio frequency(RF) energy. RF energy is a form of electrical energy that may be in thefrequency range of 300 kHz to 1 MHz, as described inEN60601-2-2:2009+A11:2011, Definition 201.3.218—HIGH FREQUENCY. Forexample, the frequencies in monopolar RF applications are typicallyrestricted to less than 5 MHz. However, in bipolar RF applications, thefrequency can be almost any value. Frequencies above 200 kHz aretypically used for monopolar applications in order to avoid the unwantedstimulation of nerves and muscles which would result from the use of lowfrequency current. Lower frequencies may be used for bipolar techniquesif a risk analysis shows the possibility of neuromuscular stimulationhas been mitigated to an acceptable level. Normally, frequencies above 5MHz are not used in order to minimize the problems associated with highfrequency leakage currents. It is generally recognized that 10 mA is thelower threshold of thermal effects on tissue.

During its operation, an electrosurgical device can transmit lowfrequency RF energy through tissue, which causes ionic agitation, orfriction, in effect resistive heating, thereby increasing thetemperature of the tissue. Because a sharp boundary may be createdbetween the affected tissue and the surrounding tissue, surgeons canoperate with a high level of precision and control, without sacrificingun-targeted adjacent tissue. The low operating temperatures of RF energymay be useful for removing, shrinking, or sculpting soft tissue whilesimultaneously sealing blood vessels. RF energy may work particularlywell on connective tissue, which is primarily comprised of collagen andshrinks when contacted by heat.

Due to their unique drive signal, sensing and feedback needs, ultrasonicand electrosurgical devices have generally required differentgenerators. Additionally, in cases where the instrument is disposable orinterchangeable with a handpiece, ultrasonic and electrosurgicalgenerators are limited in their ability to recognize the particularinstrument configuration being used and to optimize control anddiagnostic processes accordingly. Moreover, capacitive coupling betweenthe non-isolated and patient-isolated circuits of the generator,especially in cases where higher voltages and frequencies are used, mayresult in exposure of a patient to unacceptable levels of leakagecurrent.

Furthermore, due to their unique drive signal, sensing and feedbackneeds, ultrasonic and electrosurgical devices have generally requireddifferent user interfaces for the different generators. In suchconventional ultrasonic and electrosurgical devices, one user interfaceis configured for use with an ultrasonic instrument whereas a differentuser interface may be configured for use with an electrosurgicalinstrument. Such user interfaces include hand and/or foot activated userinterfaces such as hand activated switches and/or foot activatedswitches. As various aspects of combined generators for use with bothultrasonic and electrosurgical instruments are contemplated in thesubsequent disclosure, additional user interfaces that are configured tooperate with both ultrasonic and/or electrosurgical instrumentgenerators also are contemplated.

Additional user interfaces for providing feedback, whether to the useror other machine, are contemplated within the subsequent disclosure toprovide feedback indicating an operating mode or status of either anultrasonic and/or electrosurgical instrument. Providing user and/ormachine feedback for operating a combination ultrasonic and/orelectrosurgical instrument will require providing sensory feedback to auser and electrical/mechanical/electro-mechanical feedback to a machine.Feedback devices that incorporate visual feedback devices (e.g., an LCDdisplay screen, LED indicators), audio feedback devices (e.g., aspeaker, a buzzer) or tactile feedback devices (e.g., haptic actuators)for use in combined ultrasonic and/or electrosurgical instruments arecontemplated in the subsequent disclosure.

Other electrical surgical instruments include, without limitation,irreversible and/or reversible electroporation, and/or microwavetechnologies, among others. Accordingly, the techniques disclosed hereinare applicable to ultrasonic, bipolar or monopolar RF (electrosurgical),irreversible and/or reversible electroporation, and/or microwave basedsurgical instruments, among others.

Various aspects are directed to improved ultrasonic surgical devices,electrosurgical devices and generators for use therewith. Aspects of theultrasonic surgical devices can be configured for transecting and/orcoagulating tissue during surgical procedures, for example. Aspects ofthe electrosurgical devices can be configured for transecting,coagulating, scaling, welding and/or desiccating tissue during surgicalprocedures, for example.

Aspects of the generator utilize high-speed analog-to-digital sampling(e.g., approximately 200× oversampling, depending on frequency) of thegenerator drive signal current and voltage, along with digital signalprocessing, to provide a number of advantages and benefits over knowngenerator architectures. In one aspect, for example, based on currentand voltage feedback data, a value of the ultrasonic transducer staticcapacitance, and a value of the drive signal frequency, the generatormay determine the motional branch current of an ultrasonic transducer.This provides the benefit of a virtually tuned system, and simulates thepresence of a system that is tuned or resonant with any value of thestatic capacitance (e.g., C₀ in FIG. 25 ) at any frequency. Accordingly,control of the motional branch current may be realized by tuning out theeffects of the static capacitance without the need for a tuninginductor. Additionally, the elimination of the tuning inductor may notdegrade the generator's frequency lock capabilities, as frequency lockcan be realized by suitably processing the current and voltage feedbackdata.

High-speed analog-to-digital sampling of the generator drive signalcurrent and voltage, along with digital signal processing, may alsoenable precise digital filtering of the samples. For example, aspects ofthe generator may utilize a low-pass digital filter (e.g., a finiteimpulse response (FIR) filter) that rolls off between a fundamentaldrive signal frequency and a second-order harmonic to reduce theasymmetrical harmonic distortion and EMI-induced noise in current andvoltage feedback samples. The filtered current and voltage feedbacksamples represent substantially the fundamental drive signal frequency,thus enabling a more accurate impedance phase measurement with respectto the fundamental drive signal frequency and an improvement in thegenerator's ability to maintain resonant frequency lock. The accuracy ofthe impedance phase measurement may be further enhanced by averagingfalling edge and rising edge phase measurements, and by regulating themeasured impedance phase to 0°.

Various aspects of the generator may also utilize the high-speedanalog-to-digital sampling of the generator drive signal current andvoltage, along with digital signal processing, to determine real powerconsumption and other quantities with a high degree of precision. Thismay allow the generator to implement a number of useful algorithms, suchas, for example, controlling the amount of power delivered to tissue asthe impedance of the tissue changes and controlling the power deliveryto maintain a constant rate of tissue impedance increase. Some of thesealgorithms are used to determine the phase difference between thegenerator drive signal current and voltage signals. At resonance, thephase difference between the current and voltage signals is zero. Thephase changes as the ultrasonic system goes off-resonance. Variousalgorithms may be employed to detect the phase difference and adjust thedrive frequency until the ultrasonic system returns to resonance, i.e.,the phase difference between the current and voltage signals goes tozero. The phase information also may be used to infer the conditions ofthe ultrasonic blade. As discussed with particularity below, the phasechanges as a function of the temperature of the ultrasonic blade.Therefore, the phase information may be employed to control thetemperature of the ultrasonic blade. This may be done, for example, byreducing the power delivered to the ultrasonic blade when the ultrasonicblade runs too hot and increasing the power delivered to the ultrasonicblade when the ultrasonic blade runs too cold.

Various aspects of the generator may have a wide frequency range andincreased output power necessary to drive both ultrasonic surgicaldevices and electrosurgical devices. The lower voltage, higher currentdemand of electrosurgical devices may be met by a dedicated tap on awideband power transformer, thereby eliminating the need for a separatepower amplifier and output transformer. Moreover, sensing and feedbackcircuits of the generator may support a large dynamic range thataddresses the needs of both ultrasonic and electrosurgical applicationswith minimal distortion.

Various aspects may provide a simple, economical means for the generatorto read from, and optionally write to, a data circuit (e.g., asingle-wire bus device, such as a one-wire protocol EEPROM known underthe trade name “1-Wire”) disposed in an instrument attached to thehandpiece using existing multi-conductor generator/handpiece cables. Inthis way, the generator is able to retrieve and processinstrument-specific data from an instrument attached to the handpiece.This may enable the generator to provide better control and improveddiagnostics and error detection. Additionally, the ability of thegenerator to write data to the instrument makes possible newfunctionality in terms of, for example, tracking instrument usage andcapturing operational data. Moreover, the use of frequency band permitsthe backward compatibility of instruments containing a bus device withexisting generators.

Disclosed aspects of the generator provide active cancellation ofleakage current caused by unintended capacitive coupling betweennon-isolated and patient-isolated circuits of the generator. In additionto reducing patient risk, the reduction of leakage current may alsolessen electromagnetic emissions.

These and other benefits of aspects of the present disclosure will beapparent from the description to follow.

It will be appreciated that the terms “proximal” and “distal” are usedherein with reference to a clinician gripping a handpiece. Thus, an endeffector is distal with respect to the more proximal handpiece. It willbe further appreciated that, for convenience and clarity, spatial termssuch as “top” and “bottom” may also be used herein with respect to theclinician gripping the handpiece. However, surgical devices are used inmany orientations and positions, and these terms are not intended to belimiting and absolute.

FIG. 46 is an elevational exploded view of modular handheld ultrasonicsurgical instrument 6480 showing the left shell half removed from ahandle assembly 6482 exposing a device identifier communicativelycoupled to the multi-lead handle terminal assembly in accordance withone aspect of the present disclosure. In additional aspects of thepresent disclosure, an intelligent or smart battery is used to power themodular handheld ultrasonic surgical instrument 6480. However, the smartbattery is not limited to the modular handheld ultrasonic surgicalinstrument 6480 and, as will be explained, can be used in a variety ofdevices, which may or may not have power requirements (e.g., current andvoltage) that vary from one another. The smart battery assembly 6486, inaccordance with one aspect of the present disclosure, is advantageouslyable to identify the particular device to which it is electricallycoupled. It does this through encrypted or unencrypted identificationmethods. For instance, a smart battery assembly 6486 can have aconnection portion, such as connection portion 6488. The handle assembly6482 can also be provided with a device identifier communicativelycoupled to the multi-lead handle terminal assembly 6491 and operable tocommunicate at least one piece of information about the handle assembly6482. This information can pertain to the number of times the handleassembly 6482 has been used, the number of times an ultrasonictransducer/generator assembly 6484 (presently disconnected from thehandle assembly 6482) has been used, the number of times a waveguideshaft assembly 6490 (presently connected to the handle assembly 6482)has been used, the type of the waveguide shaft assembly 6490 that ispresently connected to the handle assembly 6482, the type or identity ofthe ultrasonic transducer/generator assembly 6484 that is presentlyconnected to the handle assembly 6482, and/or many othercharacteristics. When the smart battery assembly 6486 is inserted in thehandle assembly 6482, the connection portion 6488 within the smartbattery assembly 6486 makes communicating contact with the deviceidentifier of the handle assembly 6482. The handle assembly 6482,through hardware, software, or a combination thereof, is able totransmit information to the smart battery assembly 6486 (whether byself-initiation or in response to a request from the smart batteryassembly 6486). This communicated identifier is received by theconnection portion 6488 of the smart battery assembly 6486. In oneaspect, once the smart battery assembly 6486 receives the information,the communication portion is operable to control the output of the smartbattery assembly 6486 to comply with the device's specific powerrequirements.

In one aspect, the communication portion includes a processor 6493 and amemory 6497, which may be separate or a single component. The processor6493, in combination with the memory, is able to provide intelligentpower management for the modular handheld ultrasonic surgical instrument6480. This aspect is particularly advantageous because an ultrasonicdevice, such as the modular handheld ultrasonic surgical instrument6480, has a power requirement (frequency, current, and voltage) that maybe unique to the modular handheld ultrasonic surgical instrument 6480.In fact, the modular handheld ultrasonic surgical instrument 6480 mayhave a particular power requirement or limitation for one dimension ortype of outer tube 6494 and a second different power requirement for asecond type of waveguide having a different dimension, shape, and/orconfiguration.

A smart battery assembly 6486, in accordance with at least one aspect ofthe present disclosure, therefore, allows a battery assembly to be usedamongst several surgical instruments. Because the smart battery assembly6486 is able to identify to which device it is attached and is able toalter its output accordingly, the operators of various differentsurgical instruments utilizing the smart battery assembly 6486 no longerneed be concerned about which power source they are attempting toinstall within the electronic device being used. This is particularlyadvantageous in an operating environment where a battery assembly needsto be replaced or interchanged with another surgical instrument in themiddle of a complex surgical procedure.

In a further aspect of the present disclosure, the smart batteryassembly 6486 stores in a memory 6497 a record of each time a particulardevice is used. This record can be useful for assessing the end of adevice's useful or permitted life. For instance, once a device is used20 times, such batteries in the smart battery assembly 6486 connected tothe device will refuse to supply power thereto-because the device isdefined as a “no longer reliable” surgical instrument. Reliability isdetermined based on a number of factors. One factor can be wear, whichcan be estimated in a number of ways including the number of times thedevice has been used or activated. After a certain number of uses, theparts of the device can become worn and tolerances between partsexceeded. For instance, the smart battery assembly 6486 can sense thenumber of button pushes received by the handle assembly 6482 and candetermine when a maximum number of button pushes has been met orexceeded. The smart battery assembly 6486 can also monitor an impedanceof the button mechanism which can change, for instance, if the handlegets contaminated, for example, with saline.

This wear can lead to an unacceptable failure during a procedure. Insome aspects, the smart battery assembly 6486 can recognize which partsare combined together in a device and even how many uses a part hasexperienced. For instance, if the smart battery assembly 6486 is a smartbattery according to the present disclosure, it can identify the handleassembly 6482, the waveguide shaft assembly 6490, as well as theultrasonic transducer/generator assembly 6484, well before the userattempts use of the composite device. The memory 6497 within the smartbattery assembly 6486 can, for example, record a time when theultrasonic transducer/generator assembly 6484 is operated, and how,when, and for how long it is operated. If the ultrasonictransducer/generator assembly 6484 has an individual identifier, thesmart battery assembly 6486 can keep track of uses of the ultrasonictransducer/generator assembly 6484 and refuse to supply power to thatthe ultrasonic transducer/generator assembly 6484 once the handleassembly 6482 or the ultrasonic transducer/generator assembly 6484exceeds its maximum number of uses. The ultrasonic transducer/generatorassembly 6484, the handle assembly 6482, the waveguide shaft assembly6490, or other components can include a memory chip that records thisinformation as well. In this way, any number of smart batteries in thesmart battery assembly 6486 can be used with any number of ultrasonictransducer/generator assemblies 6484, staplers, vessel sealers, etc. andstill be able to determine the total number of uses, or the total timeof use (through use of the clock), or the total number of actuations,etc. of the ultrasonic transducer/generator assembly 6484, the stapler,the vessel sealer, etc. or charge or discharge cycles. Smartfunctionality may reside outside the battery assembly 6486 and mayreside in the handle assembly 6482, the ultrasonic transducer/generatorassembly 6484, and/or the shaft assembly 6490, for example.

When counting uses of the ultrasonic transducer/generator assembly 6484,to intelligently terminate the life of the ultrasonictransducer/generator assembly 6484, the surgical instrument accuratelydistinguishes between completion of an actual use of the ultrasonictransducer/generator assembly 6484 in a surgical procedure and amomentary lapse in actuation of the ultrasonic transducer/generatorassembly 6484 due to, for example, a battery change or a temporary delayin the surgical procedure. Therefore, as an alternative to simplycounting the number of activations of the ultrasonictransducer/generator assembly 6484, a real-time clock (RTC) circuit canbe implemented to keep track of the amount of time the ultrasonictransducer/generator assembly 6484 actually is shut down. From thelength of time measured, it can be determined through appropriate logicif the shutdown was significant enough to be considered the end of oneactual use or if the shutdown was too short in time to be considered theend of one use. Thus, in some applications, this method may be a moreaccurate determination of the useful life of the ultrasonictransducer/generator assembly 6484 than a simple “activations-based”algorithm, which for example, may provide that ten “activations” occurin a surgical procedure and, therefore, ten activations should indicatethat the counter is incremented by one. Generally, this type and systemof internal clocking will prevent misuse of the device that is designedto deceive a simple “activations-based” algorithm and will preventincorrect logging of a complete use in instances when there was only asimple de-mating of the ultrasonic transducer/generator assembly 6484 orthe smart battery assembly 6486 that was required for legitimatereasons.

Although the ultrasonic transducer/generator assemblies 6484 of thesurgical instrument 6480 are reusable, in one aspect a finite number ofuses may be set because the surgical instrument 6480 is subjected toharsh conditions during cleaning and sterilization. More specifically,the battery pack is configured to be sterilized. Regardless of thematerial employed for the outer surfaces, there is a limited expectedlife for the actual materials used. This life is determined by variouscharacteristics which could include, for example, the amount of timesthe pack has actually been sterilized, the time from which the pack wasmanufactured, and the number of times the pack has been recharged, toname a few. Also, the life of the battery cells themselves is limited.Software of the present disclosure incorporates inventive algorithmsthat verify the number of uses of the ultrasonic transducer/generatorassembly 6484 and smart battery assembly 6486 and disables the devicewhen this number of uses has been reached or exceeded. Analysis of thebattery pack exterior in each of the possible sterilizing methods can beperformed. Based on the harshest sterilization procedure, a maximumnumber of permitted sterilizations can be defined and that number can bestored in a memory of the smart battery assembly 6486. If it is assumedthat a charger is non-sterile and that the smart battery assembly 6486is to be used after it is charged, then the charge count can be definedas being equal to the number of sterilizations encountered by thatparticular pack.

In one aspect, the hardware in the battery pack may be to disabled tominimize or eliminate safety concerns due to continuous drain in fromthe battery cells after the pack has been disabled by software. Asituation can exist where the battery's internal hardware is incapableof disabling the battery under certain low voltage conditions. In such asituation, in an aspect, the charger can be used to “kill” the battery.Due to the fact that the battery microcontroller is OFF while thebattery is in its charger, a non-volatile, System Management Bus (SMB)based electrically erasable programmable read only memory (EEPROM) canbe used to exchange information between the battery microcontroller andthe charger. Thus, a serial EEPROM can be used to store information thatcan be written and read even when the battery microcontroller is OFF,which is very beneficial when trying to exchange information with thecharger or other peripheral devices. This example EEPROM can beconfigured to contain enough memory registers to store at least (a) ause-count limit at which point the battery should be disabled (BatteryUse Count), (b) the number of procedures the battery has undergone(Battery Procedure Count), and/or (c) a number of charges the batteryhas undergone (Charge Count), to name a few. Some of the informationstored in the EEPROM, such as the Use Count Register and Charge CountRegister are stored in write-protected sections of the EEPROM to preventusers from altering the information. In an aspect, the use and countersare stored with corresponding bit-inverted minor registers to detectdata corruption.

Any residual voltage in the SMBus lines could damage the microcontrollerand corrupt the SMBus signal. Therefore, to ensure that the SMBus linesof a battery controller do not carry a voltage while the microcontrolleris OFF, relays are provided between the external SMBus lines and thebattery microcontroller board.

During charging of the smart battery assembly 6486, an “end-of-charge”condition of the batteries within the smart battery assembly 6486 isdetermined when, for example, the current flowing into the battery fallsbelow a given threshold in a tapering manner when employing aconstant-current/constant-voltage charging scheme. To accurately detectthis “end-of-charge” condition, the battery microcontroller and buckboards are powered down and turned OFF during charging of the battery toreduce any current drain that may be caused by the boards and that mayinterfere with the tapering current detection. Additionally, themicrocontroller and buck boards are powered down during charging toprevent any resulting corruption of the SMBus signal.

With regard to the charger, in one aspect the smart battery assembly6486 is prevented from being inserted into the charger in any way otherthan the correct insertion position. Accordingly, the exterior of thesmart battery assembly 6486 is provided with charger-holding features. Acup for holding the smart battery assembly 6486 securely in the chargeris configured with a contour-matching taper geometry to prevent theaccidental insertion of the smart battery assembly 6486 in any way otherthan the correct (intended) way. It is further contemplated that thepresence of the smart battery assembly 6486 may be detectable by thecharger itself. For example, the charger may be configured to detect thepresence of the SMBus transmission from the battery protection circuit,as well as resistors that are located in the protection board. In suchcase, the charger would be enabled to control the voltage that isexposed at the charger's pins until the smart battery assembly 6486 iscorrectly seated or in place at the charger. This is because an exposedvoltage at the charger's pins would present a hazard and a risk that anelectrical short could occur across the pins and cause the charger toinadvertently begin charging.

In some aspects, the smart battery assembly 6486 can communicate to theuser through audio and/or visual feedback. For example, the smartbattery assembly 6486 can cause the LEDs to light in a pre-set way. Insuch a case, even though the microcontroller in the ultrasonictransducer/generator assembly 6484 controls the LEDs, themicrocontroller receives instructions to be carried out directly fromthe smart battery assembly 6486.

In yet a further aspect of the present disclosure, the microcontrollerin the ultrasonic transducer/generator assembly 6484, when not in usefor a predetermined period of time, goes into a sleep mode.Advantageously, when in the sleep mode, the clock speed of themicrocontroller is reduced, cutting the current drain significantly.Some current continues to be consumed because the processor continuespinging waiting to sense an input. Advantageously, when themicrocontroller is in this power-saving sleep mode, the microcontrollerand the battery controller can directly control the LEDs. For example, adecoder circuit could be built into the ultrasonic transducer/generatorassembly 6484 and connected to the communication lines such that theLEDs can be controlled independently by the processor 6493 while theultrasonic transducer/generator assembly 6484 microcontroller is “OFF”or in a “sleep mode.” This is a power-saving feature that eliminates theneed for waking up the microcontroller in the ultrasonictransducer/generator assembly 6484. Power is conserved by allowing thegenerator to be turned off while still being able to actively controlthe user-interface indicators.

Another aspect slows down one or more of the microcontrollers toconserve power when not in use. For example, the clock frequencies ofboth microcontrollers can be reduced to save power. To maintainsynchronized operation, the microcontrollers coordinate the changing oftheir respective clock frequencies to occur at about the same time, boththe reduction and, then, the subsequent increase in frequency when fullspeed operation is required. For example, when entering the idle mode,the clock frequencies are decreased and, when exiting the idle mode, thefrequencies are increased.

In an additional aspect, the smart battery assembly 6486 is able todetermine the amount of usable power left within its cells and isprogrammed to only operate the surgical instrument to which it isattached if it determines there is enough battery power remaining topredictably operate the device throughout the anticipated procedure. Forexample, the smart battery assembly 6486 is able to remain in anon-operational state if there is not enough power within the cells tooperate the surgical instrument for 20 seconds. According to one aspect,the smart battery assembly 6486 determines the amount of power remainingwithin the cells at the end of its most recent preceding function, e.g.,a surgical cutting. In this aspect, therefore, the smart batteryassembly 6486 would not allow a subsequent function to be carried outif, for example, during that procedure, it determines that the cellshave insufficient power. Alternatively, if the smart battery assembly6486 determines that there is sufficient power for a subsequentprocedure and goes below that threshold during the procedure, it wouldnot interrupt the ongoing procedure and, instead, will allow it tofinish and thereafter prevent additional procedures from occurring.

The following explains an advantage to maximizing use of the device withthe smart battery assembly 6486 of the present disclosure. In thisexample, a set of different devices have different ultrasonictransmission waveguides. By definition, the waveguides could have arespective maximum allowable power limit where exceeding that powerlimit overstresses the waveguide and eventually causes it to fracture.One waveguide from the set of waveguides will naturally have thesmallest maximum power tolerance. Because prior-art batteries lackintelligent battery power management, the output of prior-art batteriesmust be limited by a value of the smallest maximum allowable power inputfor the smallest/thinnest/most-frail waveguide in the set that isenvisioned to be used with the device/battery. This would be true eventhough larger, thicker waveguides could later be attached to that handleand, by definition, allow a greater force to be applied. This limitationis also true for maximum battery power. For example, if one battery isdesigned to be used in multiple devices, its maximum output power willbe limited to the lowest maximum power rating of any of the devices inwhich it is to be used. With such a configuration, one or more devicesor device configurations would not be able to maximize use of thebattery because the battery does not know the particular device'sspecific limits.

In one aspect, the smart battery assembly 6486 may be employed tointelligently circumvent the above-mentioned ultrasonic devicelimitations. The smart battery assembly 6486 can produce one output forone device or a particular device configuration and the same smartbattery assembly 6486 can later produce a different output for a seconddevice or device configuration. This universal smart battery surgicalsystem lends itself well to the modem operating room where space andtime are at a premium. By having a smart battery pack operate manydifferent devices, the nurses can easily manage the storage, retrieval,and inventory of these packs. Advantageously, in one aspect the smartbattery system according to the present disclosure may employ one typeof charging station, thus increasing ease and efficiency of use anddecreasing cost of surgical room charging equipment.

In addition, other surgical instruments, such as an electric stapler,may have a different power requirement than that of the modular handheldultrasonic surgical instrument 6480. In accordance with various aspectsof the present disclosure, a smart battery assembly 6486 can be usedwith any one of a series of surgical instruments and can be made totailor its own power output to the particular device in which it isinstalled. In one aspect, this power tailoring is performed bycontrolling the duty cycle of a switched mode power supply, such asbuck, buck-boost, boost, or other configuration, integral with orotherwise coupled to and controlled by the smart battery assembly 6486.In other aspects, the smart battery assembly 6486 can dynamically changeits power output during device operation. For instance, in vesselsealing devices, power management provides improved tissue sealing. Inthese devices, large constant current values are needed. The total poweroutput needs to be adjusted dynamically because, as the tissue issealed, its impedance changes. Aspects of the present disclosure providethe smart battery assembly 6486 with a variable maximum current limit.The current limit can vary from one application (or device) to another,based on the requirements of the application or device.

FIG. 47 is a detail view of a trigger 6483 portion and switch of theultrasonic surgical instrument 6480 shown in FIG. 46 , in accordancewith at least one aspect of the present disclosure. The trigger 6483 isoperably coupled to the jaw member 6495 of the end effector 6492. Theultrasonic blade 6496 is energized by the ultrasonictransducer/generator assembly 6484 upon activating the activation switch6485. Continuing now with FIG. 46 and also looking to FIG. 47 , thetrigger 6483 and the activation switch 6485 are shown as components ofthe handle assembly 6482. The trigger 6483 activates the end effector6492, which has a cooperative association with the ultrasonic blade 6496of the waveguide shaft assembly 6490 to enable various kinds of contactbetween the end effector jaw member 6495 and the ultrasonic blade 6496with tissue and/or other substances. The jaw member 6495 of the endeffector 6492 is usually a pivoting jaw that acts to grasp or clamp ontotissue disposed between the jaw and the ultrasonic blade 6496. In oneaspect, an audible feedback is provided in the trigger that clicks whenthe trigger is fully depressed. The noise can be generated by a thinmetal part that the trigger snaps over while closing. This feature addsan audible component to user feedback that informs the user that the jawis fully compressed against the waveguide and that sufficient clampingpressure is being applied to accomplish vessel sealing. In anotheraspect, force sensors such as strain gages or pressure sensors may becoupled to the trigger 6483 to measure the force applied to the trigger6483 by the user. In another aspect, force sensors such as strain gagesor pressure sensors may be coupled to the switch 6485 button such thatdisplacement intensity corresponds to the force applied by the user tothe switch 6485 button.

The activation switch 6485, when depressed, places the modular handheldultrasonic surgical instrument 6480 into an ultrasonic operating mode,which causes ultrasonic motion at the waveguide shaft assembly 6490. Inone aspect, depression of the activation switch 6485 causes electricalcontacts within a switch to close, thereby completing a circuit betweenthe smart battery assembly 6486 and the ultrasonic transducer/generatorassembly 6484 so that electrical power is applied to the ultrasonictransducer, as previously described. In another aspect, depression ofthe activation switch 6485 closes electrical contacts to the smartbattery assembly 6486. Of course, the description of closing electricalcontacts in a circuit is, here, merely an example general description ofswitch operation. There are many alternative aspects that can includeopening contacts or processor-controlled power delivery that receivesinformation from the switch and directs a corresponding circuit reactionbased on the information.

FIG. 48 is a fragmentary, enlarged perspective view of an end effector6492, in accordance with at least one aspect of the present disclosure,from a distal end with a jaw member 6495 in an open position. Referringto FIG. 48 , a perspective partial view of the distal end 6498 of thewaveguide shaft assembly 6490 is shown. The waveguide shaft assembly6490 includes an outer tube 6494 surrounding a portion of the waveguide.The ultrasonic blade 6496 portion of the waveguide 6499 protrudes fromthe distal end 6498 of the outer tube 6494. It is the ultrasonic blade6496 portion that contacts the tissue during a medical procedure andtransfers its ultrasonic energy to the tissue. The waveguide shaftassembly 6490 also includes a jaw member 6495 that is coupled to theouter tube 6494 and an inner tube (not visible in this view). The jawmember 6495, together with the inner and outer tubes and the ultrasonicblade 6496 portion of the waveguide 6499, can be referred to as an endeffector 6492. As will be explained below, the outer tube 6494 and thenon-illustrated inner tube slide longitudinally with respect to eachother. As the relative movement between the outer tube 6494 and thenon-illustrated inner tube occurs, the jaw member 6495 pivots upon apivot point, thereby causing the jaw member 6495 to open and close. Whenclosed, the jaw member 6495 imparts a pinching force on tissue locatedbetween the jaw member 6495 and the ultrasonic blade 6496, insuringpositive and efficient blade-to-tissue contact.

FIG. 49 is a system diagram 7400 of a segmented circuit 7401 comprisinga plurality of independently operated circuit segments 7402, 7414, 7416,7420, 7424, 7428, 7434, 7440, in accordance with at least one aspect ofthe present disclosure. A circuit segment of the plurality of circuitsegments of the segmented circuit 7401 comprises one or more circuitsand one or more sets of machine executable instructions stored in one ormore memory devices. The one or more circuits of a circuit segment arecoupled to for electrical communication through one or more wired orwireless connection media. The plurality of circuit segments areconfigured to transition between three modes comprising a sleep mode, astandby mode and an operational mode.

In one aspect shown, the plurality of circuit segments 7402, 7414, 7416,7420, 7424, 7428, 7434, 7440 start first in the standby mode, transitionsecond to the sleep mode, and transition third to the operational mode.However, in other aspects, the plurality of circuit segments maytransition from any one of the three modes to any other one of the threemodes. For example, the plurality of circuit segments may transitiondirectly from the standby mode to the operational mode. Individualcircuit segments may be placed in a particular state by the voltagecontrol circuit 7408 based on the execution by a processor of machineexecutable instructions. The states comprise a deenergized state, a lowenergy state, and an energized state. The deenergized state correspondsto the sleep mode, the low energy state corresponds to the standby mode,and the energized state corresponds to the operational mode. Transitionto the low energy state may be achieved by, for example, the use of apotentiometer.

In one aspect, the plurality of circuit segments 7402, 7414, 7416, 7420,7424, 7428, 7434, 7440 may transition from the sleep mode or the standbymode to the operational mode in accordance with an energizationsequence. The plurality of circuit segments also may transition from theoperational mode to the standby mode or the sleep mode in accordancewith a deenergization sequence. The energization sequence and thedeenergization sequence may be different. In some aspects, theenergization sequence comprises energizing only a subset of circuitsegments of the plurality of circuit segments. In some aspects, thedeenergization sequence comprises deenergizing only a subset of circuitsegments of the plurality of circuit segments.

Referring back to the system diagram 7400 in FIG. 49 , the segmentedcircuit 7401 comprise a plurality of circuit segments comprising atransition circuit segment 7402, a processor circuit segment 7414, ahandle circuit segment 7416, a communication circuit segment 7420, adisplay circuit segment 7424, a motor control circuit segment 7428, anenergy treatment circuit segment 7434, and a shaft circuit segment 7440.The transition circuit segment comprises a wake up circuit 7404, a boostcurrent circuit 7406, a voltage control circuit 7408, a safetycontroller 7410 and a POST controller 7412. The transition circuitsegment 7402 is configured to implement a deenergization and anenergization sequence, a safety detection protocol, and a POST.

In some aspects, the wake up circuit 7404 comprises an accelerometerbutton sensor 7405. In aspects, the transition circuit segment 7402 isconfigured to be in an energized state while other circuit segments ofthe plurality of circuit segments of the segmented circuit 7401 areconfigured to be in a low energy state, a deenergized state or anenergized state. The accelerometer button sensor 7405 may monitormovement or acceleration of the surgical instrument 6480 describedherein. For example, the movement may be a change in orientation orrotation of the surgical instrument. The surgical instrument may bemoved in any direction relative to a three dimensional Euclidean spaceby for example, a user of the surgical instrument. When theaccelerometer button sensor 7405 senses movement or acceleration, theaccelerometer button sensor 7405 sends a signal to the voltage controlcircuit 7408 to cause the voltage control circuit 7408 to apply voltageto the processor circuit segment 7414 to transition the processor and avolatile memory to an energized state. In aspects, the processor and thevolatile memory are in an energized state before the voltage controlcircuit 7409 applies voltage to the processor and the volatile memory.In the operational mode, the processor may initiate an energizationsequence or a deenergization sequence. In various aspects, theaccelerometer button sensor 7405 may also send a signal to the processorto cause the processor to initiate an energization sequence or adeenergization sequence. In some aspects, the processor initiates anenergization sequence when the majority of individual circuit segmentsare in a low energy state or a deenergized state. In other aspects, theprocessor initiates a deenergization sequence when the majority ofindividual circuit segments are in an energized state.

Additionally or alternatively, the accelerometer button sensor 7405 maysense external movement within a predetermined vicinity of the surgicalinstrument. For example, the accelerometer button sensor 7405 may sensea user of the surgical instrument 6480 described herein moving a hand ofthe user within the predetermined vicinity. When the accelerometerbutton sensor 7405 senses this external movement, the accelerometerbutton sensor 7405 may send a signal to the voltage control circuit 7408and a signal to the processor, as previously described. After receivingthe sent signal, the processor may initiate an energization sequence ora deenergization sequence to transition one or more circuit segmentsbetween the three modes. In aspects, the signal sent to the voltagecontrol circuit 7408 is sent to verify that the processor is inoperational mode. In some aspects, the accelerometer button sensor 7405may sense when the surgical instrument has been dropped and send asignal to the processor based on the sensed drop. For example, thesignal can indicate an error in the operation of an individual circuitsegment. One or more sensors may sense damage or malfunctioning of theaffected individual circuit segments. Based on the sensed damage ormalfunctioning, the POST controller 7412 may perform a POST of thecorresponding individual circuit segments.

An energization sequence or a deenergization sequence may be definedbased on the accelerometer button sensor 7405. For example, theaccelerometer button sensor 7405 may sense a particular motion or asequence of motions that indicates the selection of a particular circuitsegment of the plurality of circuit segments. Based on the sensed motionor series of sensed motions, the accelerometer button sensor 7405 maytransmit a signal comprising an indication of one or more circuitsegments of the plurality of circuit segments to the processor when theprocessor is in an energized state. Based on the signal, the processordetermines an energization sequence comprising the selected one or morecircuit segments. Additionally or alternatively, a user of the surgicalinstruments 6480 described herein may select a number and order ofcircuit segments to define an energization sequence or a deenergizationsequence based on interaction with a graphical user interface (GUI) ofthe surgical instrument.

In various aspects, the accelerometer button sensor 7405 may send asignal to the voltage control circuit 7408 and a signal to the processoronly when the accelerometer button sensor 7405 detects movement of thesurgical instrument 6480 described herein or external movement within apredetermined vicinity above a predetermined threshold. For example, asignal may only be sent if movement is sensed for 5 or more seconds orif the surgical instrument is moved 5 or more inches. In other aspects,the accelerometer button sensor 7405 may send a signal to the voltagecontrol circuit 7408 and a signal to the processor only when theaccelerometer button sensor 7405 detects oscillating movement of thesurgical instrument A predetermined threshold reduces inadvertenttransition of circuit segments of the surgical instrument. As previouslydescribed, the transition may comprise a transition to operational modeaccording to an energization sequence, a transition to low energy modeaccording to a deenergization sequence, or a transition to sleep modeaccording to a deenergization sequence. In some aspects, the surgicalinstrument comprises an actuator that may be actuated by a user of thesurgical instrument. The actuation is sensed by the accelerometer buttonsensor 7405. The actuator may be a slider, a toggle switch, or amomentary contact switch. Based on the sensed actuation, theaccelerometer button sensor 7405 may send a signal to the voltagecontrol circuit 7408 and a signal to the processor.

The boost current circuit 7406 is coupled to a battery. The boostcurrent circuit 7406 is a current amplifier, such as a relay ortransistor, and is configured to amplify the magnitude of a current ofan individual circuit segment. The initial magnitude of the currentcorresponds to the source voltage provided by the battery to thesegmented circuit 7401. Suitable relays include solenoids. Suitabletransistors include field-effect transistors (FET), MOSFET, and bipolarjunction transistors (BJT). The boost current circuit 7406 may amplifythe magnitude of the current corresponding to an individual circuitsegment or circuit which requires more current draw during operation ofthe surgical instruments 6480 described herein. For example, an increasein current to the motor control circuit segment 7428 may be providedwhen a motor of the surgical instrument requires more input power. Theincrease in current provided to an individual circuit segment may causea corresponding decrease in current of another circuit segment orcircuit segments. Additionally or alternatively, the increase in currentmay correspond to voltage provided by an additional voltage sourceoperating in conjunction with the battery.

The voltage control circuit 7408 is coupled to the battery. The voltagecontrol circuit 7408 is configured to provide voltage to or removevoltage from the plurality of circuit segments. The voltage controlcircuit 7408 is also configured to increase or reduce voltage providedto the plurality of circuit segments of the segmented circuit 7401. Invarious aspects, the voltage control circuit 7408 comprises acombinational logic circuit such as a multiplexer (MUX) to selectinputs, a plurality of electronic switches, and a plurality of voltageconverters. An electronic switch of the plurality of electronic switchesmay be configured to switch between an open and closed configuration todisconnect or connect an individual circuit segment to or from thebattery. The plurality of electronic switches may be solid state devicessuch as transistors or other types of switches such as wirelessswitches, ultrasonic switches, accelerometers, inertial sensors, amongothers. The combinational logic circuit is configured to select anindividual electronic switch for switching to an open configuration toenable application of voltage to the corresponding circuit segment. Thecombination logic circuit also is configured to select an individualelectronic switch for switching to a closed configuration to enableremoval of voltage from the corresponding circuit segment. By selectinga plurality of individual electronic switches, the combination logiccircuit may implement a deenergization sequence or an energizationsequence. The plurality of voltage converters may provide a stepped-upvoltage or a stepped-down voltage to the plurality of circuit segments.The voltage control circuit 7408 may also comprise a microprocessor andmemory device.

The safety controller 7410 is configured to perform safety checks forthe circuit segments. In some aspects, the safety controller 7410performs the safety checks when one or more individual circuit segmentsare in the operational mode. The safety checks may be performed todetermine whether there are any errors or defects in the functioning oroperation of the circuit segments. The safety controller 7410 maymonitor one or more parameters of the plurality of circuit segments. Thesafety controller 7410 may verify the identity and operation of theplurality of circuit segments by comparing the one or more parameterswith predefined parameters. For example, if an RF energy modality isselected, the safety controller 7410 may verify that an articulationparameter of the shaft matches a predefined articulation parameter toverify the operation of the RF energy modality of the surgicalinstrument 6480 described herein. In some aspects, the safety controller7410 may monitor, by the sensors, a predetermined relationship betweenone or more properties of the surgical instrument to detect a fault. Afault may arise when the one or more properties are inconsistent withthe predetermined relationship. When the safety controller 7410determines that a fault exists, an error exists, or that some operationof the plurality of circuit segments was not verified, the safetycontroller 7410 prevents or disables operation of the particular circuitsegment where the fault, error or verification failure originated.

The POST controller 7412 performs a POST to verify proper operation ofthe plurality of circuit segments. In some aspects, the POST isperformed for an individual circuit segment of the plurality of circuitsegments prior to the voltage control circuit 7408 applying a voltage tothe individual circuit segment to transition the individual circuitsegment from standby mode or sleep mode to operational mode. If theindividual circuit segment does not pass the POST, the particularcircuit segment does not transition from standby mode or sleep mode tooperational mode. POST of the handle circuit segment 7416 may comprise,for example, testing whether the handle control sensors 7418 sense anactuation of a handle control of the surgical instrument 6480 describedherein. In some aspects, the POST controller 7412 may transmit a signalto the accelerometer button sensor 7405 to verify the operation of theindividual circuit segment as part of the POST. For example, afterreceiving the signal, the accelerometer button sensor 7405 may prompt auser of the surgical instrument to move the surgical instrument to aplurality of varying locations to confirm operation of the surgicalinstrument. The accelerometer button sensor 7405 may also monitor anoutput of a circuit segment or a circuit of a circuit segment as part ofthe POST. For example, the accelerometer button sensor 7405 can sense anincremental motor pulse generated by the motor 7432 to verify operation.A motor controller of the motor control circuit 7430 may be used tocontrol the motor 7432 to generate the incremental motor pulse.

In various aspects, the surgical instrument 6480 described herein maycomprise additional accelerometer button sensors. The POST controller7412 may also execute a control program stored in the memory device ofthe voltage control circuit 7408. The control program may cause the POSTcontroller 7412 to transmit a signal requesting a matching encryptedparameter from a plurality of circuit segments. Failure to receive amatching encrypted parameter from an individual circuit segmentindicates to the POST controller 7412 that the corresponding circuitsegment is damaged or malfunctioning. In some aspects, if the POSTcontroller 7412 determines based on the POST that the processor isdamaged or malfunctioning, the POST controller 7412 may send a signal toone or more secondary processors to cause one or more secondaryprocessors to perform critical functions that the processor is unable toperform. In some aspects, if the POST controller 7412 determines basedon the POST that one or more circuit segments do not operate properly,the POST controller 7412 may initiate a reduced performance mode ofthose circuit segments operating properly while locking out thosecircuit segments that fail POST or do not operate properly. A locked outcircuit segment may function similarly to a circuit segment in standbymode or sleep mode.

The processor circuit segment 7414 comprises the processor and thevolatile memory. The processor is configured to initiate an energizationor a deenergization sequence. To initiate the energization sequence, theprocessor transmits an energizing signal to the voltage control circuit7408 to cause the voltage control circuit 7408 to apply voltage to theplurality or a subset of the plurality of circuit segments in accordancewith the energization sequence. To initiate the deenergization sequence,the processor transmits a deenergizing signal to the voltage controlcircuit 7408 to cause the voltage control circuit 7408 to remove voltagefrom the plurality or a subset of the plurality of circuit segments inaccordance with the deenergization sequence.

The handle circuit segment 7416 comprises handle control sensors 7418.The handle control sensors 7418 may sense an actuation of one or morehandle controls of the surgical instrument 6480 described herein. Invarious aspects, the one or more handle controls comprise a clampcontrol, a release button, an articulation switch, an energy activationbutton, and/or any other suitable handle control. The user may activatethe energy activation button to select between an RF energy mode, anultrasonic energy mode or a combination RF and ultrasonic energy mode.The handle control sensors 7418 may also facilitate attaching a modularhandle to the surgical instrument. For example, the handle controlsensors 7418 may sense proper attachment of the modular handle to thesurgical instrument and indicate the sensed attachment to a user of thesurgical instrument. The LCD display 7426 may provide a graphicalindication of the sensed attachment. In some aspects, the handle controlsensors 7418 senses actuation of the one or more handle controls. Basedon the sensed actuation, the processor may initiate either anenergization sequence or a deenergization sequence.

The communication circuit segment 7420 comprises a communication circuit7422. The communication circuit 7422 comprises a communication interfaceto facilitate signal communication between the individual circuitsegments of the plurality of circuit segments. In some aspects, thecommunication circuit 7422 provides a path for the modular components ofthe surgical instrument 6480 described herein to communicateelectrically. For example, a modular shaft and a modular transducer,when attached together to the handle of the surgical instrument, canupload control programs to the handle through the communication circuit7422.

The display circuit segment 7424 comprises a LCD display 7426. The LCDdisplay 7426 may comprise a liquid crystal display screen, LEDindicators, etc. In some aspects, the LCD display 7426 is an organiclight-emitting diode (OLED) screen. A display may be placed on, embeddedin, or located remotely from the surgical instrument 6480 describedherein. For example, the display can be placed on the handle of thesurgical instrument. The display is configured to provide sensoryfeedback to a user. In various aspects, the LCD display 7426 furthercomprises a backlight. In some aspects, the surgical instrument may alsocomprise audio feedback devices such as a speaker or a buzzer andtactile feedback devices such as a haptic actuator.

The motor control circuit segment 7428 comprises a motor control circuit7430 coupled to a motor 7432. The motor 7432 is coupled to the processorby a driver and a transistor, such as a FET. In various aspects, themotor control circuit 7430 comprises a motor current sensor in signalcommunication with the processor to provide a signal indicative of ameasurement of the current draw of the motor to the processor. Theprocessor transmits the signal to the display. The display receives thesignal and displays the measurement of the current draw of the motor7432. The processor may use the signal, for example, to monitor that thecurrent draw of the motor 7432 exists within an acceptable range, tocompare the current draw to one or more parameters of the plurality ofcircuit segments, and to determine one or more parameters of a patienttreatment site. In various aspects, the motor control circuit 7430comprises a motor controller to control the operation of the motor. Forexample, the motor control circuit 7430 controls various motorparameters, such as by adjusting the velocity, torque and accelerationof the motor 7432. The adjusting is done based on the current throughthe motor 7432 measured by the motor current sensor.

In various aspects, the motor control circuit 7430 comprises a forcesensor to measure the force and torque generated by the motor 7432. Themotor 7432 is configured to actuate a mechanism of the surgicalinstruments 6480 described herein. For example, the motor 7432 isconfigured to control actuation of the shaft of the surgical instrumentto realize clamping, rotation and articulation functionality. Forexample, the motor 7432 may actuate the shaft to realize a clampingmotion with jaws of the surgical instrument. The motor controller maydetermine whether the material clamped by the jaws is tissue or metal.The motor controller may also determine the extent to which the jawsclamp the material. For example, the motor controller may determine howopen or closed the jaws are based on the derivative of sensed motorcurrent or motor voltage. In some aspects, the motor 7432 is configuredto actuate the transducer to cause the transducer to apply torque to thehandle or to control articulation of the surgical instrument. The motorcurrent sensor may interact with the motor controller to set a motorcurrent limit. When the current meets the predefined threshold limit,the motor controller initiates a corresponding change in a motor controloperation. For example, exceeding the motor current limit causes themotor controller to reduce the current draw of the motor.

The energy treatment circuit segment 7434 comprises a RF amplifier andsafety circuit 7436 and an ultrasonic signal generator circuit 7438 toimplement the energy modular functionality of the surgical instrument6480 described herein. In various aspects, the RF amplifier and safetycircuit 7436 is configured to control the RF modality of the surgicalinstrument by generating an RF signal. The ultrasonic signal generatorcircuit 7438 is configured to control the ultrasonic energy modality bygenerating an ultrasonic signal. The RF amplifier and safety circuit7436 and an ultrasonic signal generator circuit 7438 may operate inconjunction to control the combination RF and ultrasonic energymodality.

The shaft circuit segment 7440 comprises a shaft module controller 7442,a modular control actuator 7444, one or more end effector sensors 7446,and a non volatile memory 7448. The shaft module controller 7442 isconfigured to control a plurality of shaft modules comprising thecontrol programs to be executed by the processor. The plurality of shaftmodules implements a shaft modality, such as ultrasonic, combinationultrasonic and RF, RF I-blade, and RF-opposable jaw. The shaft modulecontroller 7442 can select shaft modality by selecting the correspondingshaft module for the processor to execute. The modular control actuator7444 is configured to actuate the shaft according to the selected shaftmodality. After actuation is initiated, the shaft articulates the endeffector according to the one or more parameters, routines or programsspecific to the selected shaft modality and the selected end effectormodality. The one or more end effector sensors 7446 located at the endeffector may include force sensors, temperature sensors, current sensorsor motion sensors. The one or more end effector sensors 7446 transmitdata about one or more operations of the end effector, based on theenergy modality implemented by the end effector. In various aspects, theenergy modalities include an ultrasonic energy modality, a RF energymodality, or a combination of the ultrasonic energy modality and the RFenergy modality. The non volatile memory 7448 stores the shaft controlprograms. A control program comprises one or more parameters, routinesor programs specific to the shaft. In various aspects, the non volatilememory 7448 may be an ROM, EPROM, EEPROM or flash memory. The nonvolatile memory 7448 stores the shaft modules corresponding to theselected shaft of the surgical instrument 6480 described herein in. Theshaft modules may be changed or upgraded in the non volatile memory 7448by the shaft module controller 7442, depending on the surgicalinstrument shaft to be used in operation.

FIG. 50 is a schematic diagram of a circuit 7925 of various componentsof a surgical instrument with motor control functions, in accordancewith at least one aspect of the present disclosure. In various aspects,the surgical instrument 6480 described herein may include a drivemechanism 7930 which is configured to drive shafts and/or gearcomponents in order to perform the various operations associated withthe surgical instrument 6480. In one aspect, the drive mechanism 7930includes a rotation drivetrain 7932 configured to rotate an endeffector, for example, about a longitudinal axis relative to handlehousing. The drive mechanism 7930 further includes a closure drivetrain7934 configured to close a jaw member to grasp tissue with the endeffector. In addition, the drive mechanism 7930 includes a firing drivetrain 7936 configured to open and close a clamp arm portion of the endeffector to grasp tissue with the end effector.

The drive mechanism 7930 includes a selector gearbox assembly 7938 thatcan be located in the handle assembly of the surgical instrument.Proximal to the selector gearbox assembly 7938 is a function selectionmodule which includes a first motor 7942 that functions to selectivelymove gear elements within the selector gearbox assembly 7938 toselectively position one of the drivetrains 7932, 7934, 7936 intoengagement with an input drive component of an optional second motor7944 and motor drive circuit 7946 (shown in dashed line to indicate thatthe second motor 7944 and motor drive circuit 7946 are optionalcomponents).

Still referring to FIG. 50 , the motors 7942, 7944 are coupled to motorcontrol circuits 7946, 7948, respectively, which are configured tocontrol the operation of the motors 7942, 7944 including the flow ofelectrical energy from a power source 7950 to the motors 7942, 7944. Thepower source 7950 may be a DC battery (e.g., rechargeable lead-based,nickel-based, lithium-ion based, battery etc.) or any other power sourcesuitable for providing electrical energy to the surgical instrument.

The surgical instrument further includes a microcontroller 7952(“controller”). In certain instances, the controller 7952 may include amicroprocessor 7954 (“processor”) and one or more computer readablemediums or memory units 7956 (“memory”). In certain instances, thememory 7956 may store various program instructions, which when executedmay cause the processor 7954 to perform a plurality of functions and/orcalculations described herein. The power source 7950 can be configuredto supply power to the controller 7952, for example.

The processor 7954 may be in communication with the motor controlcircuit 7946. In addition, the memory 7956 may store programinstructions, which when executed by the processor 7954 in response to auser input 7958 or feedback elements 7960, may cause the motor controlcircuit 7946 to motivate the motor 7942 to generate at least onerotational motion to selectively move gear elements within the selectorgearbox assembly 7938 to selectively position one of the drivetrains7932, 7934, 7936 into engagement with the input drive component of thesecond motor 7944. Furthermore, the processor 7954 can be incommunication with the motor control circuit 7948. The memory 7956 alsomay store program instructions, which when executed by the processor7954 in response to a user input 7958, may cause the motor controlcircuit 7948 to motivate the motor 7944 to generate at least onerotational motion to drive the drivetrain engaged with the input drivecomponent of the second motor 7948, for example.

The controller 7952 and/or other controllers of the present disclosuremay be implemented using integrated and/or discrete hardware elements,software elements, and/or a combination of both. Examples of integratedhardware elements may include processors, microprocessors,microcontrollers, integrated circuits, ASICs, PLDs, DSPs, FPGAs, logicgates, registers, semiconductor devices, chips, microchips, chip sets,microcontrollers, system on a chip (SoC), and/or single in-line package(SIP). Examples of discrete hardware elements may include circuitsand/or circuit elements such as logic gates, field effect transistors,bipolar transistors, resistors, capacitors, inductors, and/or relays. Incertain instances, the controller 7952 may include a hybrid circuitcomprising discrete and integrated circuit elements or components on oneor more substrates, for example.

In certain instances, the controller 7952 and/or other controllers ofthe present disclosure may be an LM 4F230H5QR, available from TexasInstruments, for example. In certain instances, the Texas InstrumentsLM4F230H5QR is an ARM Cortex-M4F Processor Core comprising on-chipmemory of 256 KB single-cycle flash memory, or other non-volatilememory, up to 40 MHz, a prefetch buffer to improve performance above 40MHz, a 32 KB single-cycle SRAM, internal ROM loaded with StellarisWare®software, 2 KB EEPROM, one or more PWM modules, one or more QEI analog,one or more 12-bit ADC with 12 analog input channels, among otherfeatures that are readily available. Other microcontrollers may bereadily substituted for use with the present disclosure. Accordingly,the present disclosure should not be limited in this context.

In various instances, one or more of the various steps described hereincan be performed by a finite state machine comprising either acombinational logic circuit or a sequential logic circuit, where eitherthe combinational logic circuit or the sequential logic circuit iscoupled to at least one memory circuit. The at least one memory circuitstores a current state of the finite state machine. The combinational orsequential logic circuit is configured to cause the finite state machineto the steps. The sequential logic circuit may be synchronous orasynchronous. In other instances, one or more of the various stepsdescribed herein can be performed by a circuit that includes acombination of the processor 7958 and the finite state machine, forexample.

In various instances, it can be advantageous to be able to assess thestate of the functionality of a surgical instrument to ensure its properfunction. It is possible, for example, for the drive mechanism, asexplained above, which is configured to include various motors,drivetrains, and/or gear components in order to perform the variousoperations of the surgical instrument, to wear out over time. This canoccur through normal use, and in some instances the drive mechanism canwear out faster due to abuse conditions. In certain instances, asurgical instrument can be configured to perform self-assessments todetermine the state, e.g. health, of the drive mechanism and it variouscomponents.

For example, the self-assessment can be used to determine when thesurgical instrument is capable of performing its function before are-sterilization or when some of the components should be replacedand/or repaired. Assessment of the drive mechanism and its components,including but not limited to the rotation drivetrain 7932, the closuredrivetrain 7934, and/or the firing drivetrain 7936, can be accomplishedin a variety of ways. The magnitude of deviation from a predictedperformance can be used to determine the likelihood of a sensed failureand the severity of such failure. Several metrics can be used including:Periodic analysis of repeatably predictable events, Peaks or drops thatexceed an expected threshold, and width of the failure.

In various instances, a signature waveform of a properly functioningdrive mechanism or one or more of its components can be employed toassess the state of the drive mechanism or the one or more of itscomponents. One or more vibration sensors can be arranged with respectto a properly functioning drive mechanism or one or more of itscomponents to record various vibrations that occur during operation ofthe properly functioning drive mechanism or the one or more of itscomponents. The recorded vibrations can be employed to create thesignature waveform. Future waveforms can be compared against thesignature waveform to assess the state of the drive mechanism and itscomponents.

Still referring to FIG. 50 , the surgical instrument 7930 includes adrivetrain failure detection module 7962 configured to record andanalyze one or more acoustic outputs of one or more of the drivetrains7932, 7934, 7936. The processor 7954 can be in communication with orotherwise control the module 7962. As described below in greater detail,the module 7962 can be embodied as various means, such as circuitry,hardware, a computer program product comprising a computer readablemedium (for example, the memory 7956) storing computer readable programinstructions that are executable by a processing device (for example,the processor 7954), or some combination thereof. In some aspects, theprocessor 36 can include, or otherwise control the module 7962.

Turning now to FIG. 51 , the end effector 8400 comprises RF data sensors8406, 8408 a, 8408 b located on the jaw member 8402. The end effector8400 comprises a jaw member 8402 and an ultrasonic blade 8404. The jawmember 8402 is shown clamping tissue 8410 located between the jaw member8402 and the ultrasonic blade 8404. A first sensor 8406 is located in acenter portion of the jaw member 8402. Second and third sensors 8408 a,8408 b are located on lateral portions of the jaw member 8402. Thesensors 8406, 8408 a, 8408 b are mounted or formed integrally with aflexible circuit 8412 (shown more particularly in FIG. 52 ) configuredto be fixedly mounted to the jaw member 8402.

The end effector 8400 is an example end effector for a surgicalinstrument. The sensors 8406, 8408 a, 8408 b are electrically connectedto a control circuit such as the control circuit 7400 (FIG. 63 ) viainterface circuits. The sensors 8406, 8408 a, 8408 b are battery poweredand the signals generated by the sensors 8406, 8408 a, 8408 b areprovided to analog and/or digital processing circuits of the controlcircuit.

In one aspect, the first sensor 8406 is a force sensor to measure anormal force F3 applied to the tissue 8410 by the jaw member 8402. Thesecond and third sensors 8408 a, 8408 b include one or more elements toapply RF energy to the tissue 8410, measure tissue impedance, down forceF1, transverse forces F2, and temperature, among other parameters.Electrodes 8409 a, 8409 b are electrically coupled to an energy sourceand apply RF energy to the tissue 8410. In one aspect, the first sensor8406 and the second and third sensors 8408 a, 8408 b are strain gaugesto measure force or force per unit area. It will be appreciated that themeasurements of the down force F1, the lateral forces F2, and the normalforce F3 may be readily converted to pressure by determining the surfacearea upon which the force sensors 8406, 8408 a, 8408 b are acting upon.Additionally, as described with particularity herein, the flexiblecircuit 8412 may comprise temperature sensors embedded in one or morelayers of the flexible circuit 8412. The one or more temperature sensorsmay be arranged symmetrically or asymmetrically and provide tissue 8410temperature feedback to control circuits of an ultrasonic drive circuitand an RF drive circuit.

FIG. 52 illustrates one aspect of the flexible circuit 8412 shown inFIG. 51 in which the sensors 8406, 8408 a, 8408 b may be mounted to orformed integrally therewith. The flexible circuit 8412 is configured tofixedly attach to the jaw member 8402. As shown particularly in FIG. 52, asymmetric temperature sensors 8414 a, 8414 b are mounted to theflexible circuit 8412 to enable measuring the temperature of the tissue8410 (FIG. 51 ).

FIG. 53 is an alternative system 132000 for controlling the frequency ofan ultrasonic electromechanical system 132002 and detecting theimpedance thereof, in accordance with at least one aspect of the presentdisclosure. The system 132000 may be incorporated into a generator. Aprocessor 132004 coupled to a memory 132026 programs a programmablecounter 132006 to tune to the output frequency f_(o) of the ultrasonicelectromechanical system 132002. The input frequency is generated by acrystal oscillator 132008 and is input into a fixed counter 132010 toscale the frequency to a suitable value. The outputs of the fixedcounter 132010 and the programmable counter 132006 are applied to aphase/frequency detector 132012. The output of the phase/frequencydetector 132012 is applied to an amplifier/active filter circuit 132014to generate a tuning voltage V_(t) that is applied to a voltagecontrolled oscillator 132016 (VCO). The VCO 132016 applies the outputfrequency f_(o) to an ultrasonic transducer portion of the ultrasonicelectromechanical system 132002, shown here modeled as an equivalentelectrical circuit. The voltage and current signals applied to theultrasonic transducer are monitored by a voltage sensor 132018 and acurrent sensor 132020.

The outputs of the voltage and current sensors 132018, 13020 are appliedto another phase/frequency detector 132022 to determine the phase anglebetween the voltage and current as measured by the voltage and currentsensors 132018, 13020. The output of the phase/frequency detector 132022is applied to one channel of a high speed analog to digital converter132024 (ADC) and is provided to the processor 132004 therethrough.Optionally, the outputs of the voltage and current sensors 132018,132020 may be applied to respective channels of the two-channel ADC132024 and provided to the processor 132004 for zero crossing, FFT, orother algorithm described herein for determining the phase angle betweenthe voltage and current signals applied to the ultrasonicelectromechanical system 132002.

Optionally the tuning voltage V_(t), which is proportional to the outputfrequency f_(o), may be fed back to the processor 132004 via the ADC132024. This provides the processor 132004 with a feedback signalproportional to the output frequency f_(o) and can use this feedback toadjust and control the output frequency f_(o).

Estimating the State of the Jaw (Pad Burn Through, Staples, BrokenBlade, Bone in Jaw, Tissue in Jaw)

A challenge with ultrasonic energy delivery is that ultrasonic acousticsapplied on the wrong materials or the wrong tissue can result in devicefailure, for example, clamp arm pad burn through or ultrasonic bladebreakage. It is also desirable to detect what is located in the jaws ofan end effector of an ultrasonic device and the state of the jawswithout adding additional sensors in the jaws. Locating sensors in thejaws of an ultrasonic end effector poses reliability, cost, andcomplexity challenges.

Ultrasonic spectroscopy smart blade algorithm techniques may be employedfor estimating the state of the jaw (clamp arm pad burn through,staples, broken blade, bone in jaw, tissue in jaw, back-cutting with jawclosed, etc.) based on the impedance

${Z_{g}(t)} = \frac{V_{g}(t)}{I_{g}(t)}$

of an ultrasonic transducer configured to drive an ultrasonic transducerblade, in accordance with at least one aspect of the present disclosure.The impedance Z_(g)(t), magnitude |Z|, and phase φ are plotted as afunction of frequency f.

Dynamic mechanical analysis (DMA), also known as dynamic mechanicalspectroscopy or simply mechanical spectroscopy, is a technique used tostudy and characterize materials. A sinusoidal stress is applied to amaterial, and the strain in the material is measured, allowing thedetermination of the complex modulus of the material. The spectroscopyas applied to ultrasonic devices includes exciting the tip of theultrasonic blade with a sweep of frequencies (compound signals ortraditional frequency sweeps) and measuring the resulting compleximpedance at each frequency. The complex impedance measurements of theultrasonic transducer across a range of frequencies are used in aclassifier or model to infer the characteristics of the ultrasonic endeffector. In one aspect, the present disclosure provides a technique fordetermining the state of an ultrasonic end effector (clamp arm, jaw) todrive automation in the ultrasonic device (such as disabling power toprotect the device, executing adaptive algorithms, retrievinginformation, identifying tissue, etc.).

FIG. 54 is a spectra 132030 of an ultrasonic device with a variety ofdifferent states and conditions of the end effector where the impedanceZ_(g)(t), magnitude |Z|, and phase φ are plotted as a function offrequency f, in accordance with at least one aspect of the presentdisclosure. The spectra 132030 is plotted in three-dimensional spacewhere frequency (Hz) is plotted along the x-axis, phase (Rad) is plottedalong the y-axis, and magnitude (Ohms) is plotted along the z-axis.

Spectral analysis of different jaw bites and device states producesdifferent complex impedance characteristic patterns (fingerprints)across a range of frequencies for different conditions and states. Eachstate or condition has a different characteristic pattern in 3D spacewhen plotted. These characteristic patterns can be used to estimate thecondition and state of the end effector. FIG. 54 shows the spectra forair 132032, clamp arm pad 132034, chamois 132036, staple 132038, andbroken blade 132040. The chamois 132036 may be used to characterizedifferent types of tissue.

The spectra 132030 can be evaluated by applying a low-power electricalsignal across the ultrasonic transducer to produce a non-therapeuticexcitation of the ultrasonic blade. The low-power electrical signal canbe applied in the form of a sweep or a compound Fourier series tomeasure the impedance

${Z_{g}(t)} = \frac{V_{g}(t)}{I_{g}(t)}$

across the ultrasonic transducer at a range of frequencies in series(sweep) or in parallel (compound signal) using an FFT.

Methods of Classification of New Data

For each characteristic pattern, a parametric line can be fit to thedata used for training using a polynomial, a Fourier series, or anyother form of parametric equation as may be dictated by convenience. Anew data point is then received and is classified by using the Euclideanperpendicular distance from the new data point to the trajectory thathas been fitted to the characteristic pattern training data. Theperpendicular distance of the new data point to each of the trajectories(each trajectory representing a different state or condition) is used toassign the point to a state or condition.

The probability distribution of distance of each point in the trainingdata to the fitted curve can be used to estimate the probability of acorrectly classified new data point. This essentially constructs atwo-dimensional probability distribution in a plane perpendicular to thefitted trajectory at each new data point of the fitted trajectory. Thenew data point can then be included in the training set based on itsprobability of correct classification to make an adaptive, learningclassifier that readily detects high-frequency changes in states butadapts to slow occurring deviations in system performance, such as adevice getting dirty or the pad wearing out.

FIG. 55 is a graphical representation of a plot 132042 of a set of 3Dtraining data set (S), where ultrasonic transducer impedance Z_(g)(t),magnitude |Z|, and phase φ are plotted as a function of frequency f, inaccordance with at least one aspect of the present disclosure. The 3Dtraining data set (S) plot 132042 is graphically depicted inthree-dimensional space where phase (Rad) is plotted along the x-axis,frequency (Hz) is plotted along the y-axis, magnitude (Ohms) is plottedalong the z-axis, and a parametric Fourier series is fit to the 3Dtraining data set (S). A methodology for classifying data is based onthe 3D training data set (50 is used to generate the plot 132042).

The parametric Fourier series fit to the 3D training data set (S) isgiven by:

$\overset{\rightarrow}{p} = {{\overset{\rightarrow}{a}}_{0} + {\sum\limits_{n = 1}^{\infty}\left( {{{\overset{\rightarrow}{a}}_{n}\cos\frac{n\pi t}{L}} + {{\overset{\rightarrow}{b}}_{n}\sin\frac{n\pi t}{L}}} \right)}}$

For a new point

, the perpendicular distance from

to

is found by:

D=∥

−

∥

When:

$\frac{\partial D}{\partial T} = 0$Then:

D=D _(⊥)

A probability distribution of D can be used to estimate the probabilityof a data point

belonging to the group S.

Control

Based on the classification of data measured before, during, or afteractivation of the ultrasonic transducer/ultrasonic blade, a variety ofautomated tasks and safety measures can be implemented. Similarly, thestate of the tissue located in the end effector and temperature of theultrasonic blade also can be inferred to some degree, and used to betterinform the user of the state of the ultrasonic device or protectcritical structures, etc. Temperature control of an ultrasonic blade isdescribed in commonly owned U.S. Provisional Patent Application No.62/640,417, filed Mar. 8, 2018, titled TEMPERATURE CONTROL IN ULTRASONICDEVICE AND CONTROL SYSTEM THEREFOR, which is incorporated herein byreference in its entirety.

Similarly, power delivery can be reduced when there is a highprobability that the ultrasonic blade is contacting the clamp arm pad(e.g., without tissue in between) or if there is a probability that theultrasonic blade has broken or that the ultrasonic blade is touchingmetal (e.g., a staple). Furthermore, back-cutting can be disallowed ifthe jaw is closed and no tissue is detected between the ultrasonic bladeand the clamp arm pad.

Integration of Other Data to Improve Classification

This system can be used in conjunction with other information providedby sensors, the user, metrics on the patient, environmental factors,etc., by combing the data from this process with the aforementioned datausing probability functions and a Kalman filter. The Kalman filterdetermines the maximum likelihood of a state or condition occurringgiven a plethora of uncertain measurements of varying confidence. Sincethis method allows for an assignment of probability to a newlyclassified data point, this algorithm's information can be implementedwith other measures or estimates in a Kalman filter.

FIG. 56 is a logic flow diagram 132044 depicting a control program or alogic configuration to determine jaw conditions based on the compleximpedance characteristic pattern (fingerprint), in accordance with atleast one aspect of the present disclosure. Prior to determining jawconditions based on the complex impedance characteristic pattern(fingerprint), a database is populated with reference complex impedancecharacteristic patterns or a training data sets (S) that characterizevarious jaw conditions, including, without limitation, air 132032, clamparm pad 132034, chamois 132036, staple 132038, broken blade 132040, asshown in FIG. 82 , and a variety of tissue types and conditions. Thechamois dry or wet, full byte or tip, may be used to characterizedifferent types of tissue. The data points used to generate referencecomplex impedance characteristic patterns or a training data set (S) areobtained by applying a sub-therapeutic drive signal to the ultrasonictransducer, sweeping the driving frequency over a predetermined range offrequencies from below resonance to above resonance, measuring thecomplex impedance at each of the frequencies, and recording the datapoints. The data points are then fit to a curve using a variety ofnumerical methods including polynomial curve fit, Fourier series, and/orparametric equation. A parametric Fourier series fit to the referencecomplex impedance characteristic patterns or a training data set (S) isdescribed herein.

Once the reference complex impedance characteristic patterns or atraining data sets (S) are generated, the ultrasonic instrument measuresnew data points, classifies the new points, and determines whether thenew data points should be added to the reference complex impedancecharacteristic patterns or a training data sets (S).

Turning now to the logic flow diagram of FIG. 56 , in one aspect, theprocessor or control circuit measures 132046 a complex impedance of anultrasonic transducer, wherein the complex impedance is defined as

${Z_{g}(t)} = {\frac{V_{g}(t)}{I_{g}(t)}.}$

The processor or control circuit receives 132048 a complex impedancemeasurement data point and compares 132050 the complex impedancemeasurement data point to a data point in a reference complex impedancecharacteristic pattern. The processor or control circuit classifies132052 the complex impedance measurement data point based on a result ofthe comparison analysis and assigns 132054 a state or condition of theend effector based on the result of the comparison analysis.

In one aspect, the processor or control circuit receives the referencecomplex impedance characteristic pattern from a database or memorycoupled to the processor. In one aspect, the processor or controlcircuit generates the reference complex impedance characteristic patternas follows. A drive circuit coupled to the processor or control circuitapplies a nontherapeutic drive signal to the ultrasonic transducerstarting at an initial frequency, ending at a final frequency, and at aplurality of frequencies therebetween. The processor or control circuitmeasures the impedance of the ultrasonic transducer at each frequencyand stores a data point corresponding to each impedance measurement. Theprocessor or control circuit curve fits a plurality of data points togenerate a three-dimensional curve of representative of the referencecomplex impedance characteristic pattern, wherein the magnitude |Z| andphase φ are plotted as a function of frequency f. The curve fittingincludes a polynomial curve fit, a Fourier series, and/or a parametricequation.

In one aspect, the processor or control circuit receives a new impedancemeasurement data point and classifies the new impedance measurement datapoint using a Euclidean perpendicular distance from the new impedancemeasurement data point to a trajectory that has been fitted to thereference complex impedance characteristic pattern. The processor orcontrol circuit estimates a probability that the new impedancemeasurement data point is correctly classified. The processor or controlcircuit adds the new impedance measurement data point to the referencecomplex impedance characteristic pattern based on the probability of theestimated correct classification of the new impedance measurement datapoint. In one aspect, the processor or control circuit classifies databased on a training data set (S), where the training data set (S)comprises a plurality of complex impedance measurement data, and curvefits the training data set (S) using a parametric Fourier series,wherein S is defined herein and wherein the probability distribution isused to estimate the probability of the new impedance measurement datapoint belonging to the group S.

State of Jaw Classifier Based on Model

There has been an existing interest in classifying matter located withinthe jaws of an ultrasonic device including tissue types and condition.In various aspects, it can be shown that with high data sampling andsophisticated pattern recognition this classification is possible. Theapproach is based on impedance as a function of frequency, wheremagnitude, phase, and frequency are plotted in 3D the patterns look likeribbons as shown in FIGS. 54 and 55 and the logic flow diagram of FIG.56 . This disclosure provides an alternative smart blade algorithmapproach that is based on a well-established model for piezoelectrictransducers.

By way of example, the equivalent electrical lumped parameter model isknown to be an accurate model of the physical piezoelectric transducer.It is based on the Mittag-Leffler expansion of a tangent near amechanical resonance. When the complex impedance or the complexadmittance is plotted as an imaginary component versus a real component,circles are formed. FIG. 57 is a circle plot 132056 of complex impedanceplotted as an imaginary component versus real components of apiezoelectric vibrator, in accordance with at least one aspect of thepresent disclosure. FIG. 58 is a circle plot 132058 of complexadmittance plotted as an imaginary component versus real components of apiezoelectric vibrator, in accordance with at least one aspect of thepresent disclosure. The circles depicted in FIGS. 57 and 58 are takenfrom the IEEE 177 Standard, which is incorporated herein by reference inits entirety. Tables 1-4 are taken from the IEEE 177 Standard anddisclosed herein for completeness.

The circle is created as the frequency is swept from below resonance toabove resonance. Rather than stretching the circle out in 3D, a circleis identified and the radius (r) and offsets (a, b) of the circle areestimated. These values are then compared with established values forgiven conditions. These conditions may be: 1) open nothing in jaws, 2)tip bite 3) full bite and staple in jaws. If the sweep generatesmultiple resonances, circles of different characteristics will bepresent for each resonance. Each circle will be drawn out before thenext if the resonances are separated. Rather than fitting a 3D curvewith a series approximation, the data is fitted with a circle. Theradius (r) and offsets (a, b) can be calculated using a processorprogrammed to execute a variety of mathematical or numerical techniquesdescribed below. These values may be estimated by capturing an image ofa circle and, using image processing techniques, the radius (r) andoffsets (a, b) that define the circle are estimated.

FIG. 59 is a circle plot 132060 of complex admittance for a 55.5 kHzultrasonic piezoelectric transducer for lumped parameters inputs andoutputs specified hereinbelow. Values for a lumped parameter model wereused to generate the complex admittance. A moderate load was applied inthe model. The obtained admittance circle generated in MathCad is shownin FIG. 59 . The circle plot 132060 is formed when the frequency isswept from 54 to 58 kHz.

The lumped parameter input values are:

Co=3.0 nF

Cs=8.22 pF

Ls=1.0 H

Rs=450Ω

The outputs of the model based on the inputs are:

${am} = {\frac{{D \cdot C} - {B \cdot C}}{{A \cdot C} - B^{2}} = {1{\text{.013} \cdot 10^{3}}}}$${bm} = {\frac{{A \cdot E} - {B \cdot D}}{{A \cdot C} - B^{2}} = {{- 9}5{4.5}85}}$${rm} = {{\frac{1}{fpts}\left( {\sum\limits_{i}^{fpts}\sqrt[2]{\left( {\left( {{Zout}_{1,i} = {am}} \right)^{2} + \left( {{Zout_{2,i}} - {bm}} \right)^{2}} \right)}} \right)} = {1{\text{.012} \cdot 10^{3}}}}$

The output values are used to plot the circle plot 132060 shown in FIG.59 . The circle plot 132060 has a radius (r) and the center 132062 isoffset (a, b) from the origin 132064 as follows:

r=1.012*10³

a=1.013*10³

b=−954.585

The summations A-E specified below are needed to estimate the circleplot 132060 plot for the example given in FIG. 59 , in accordance withat least one aspect of the present disclosure. Several algorithms existto calculate a fit to a circle. A circle is defined by its radius (r)and offsets (a, b) of the center from the origin:

r ²=(x−a)²+(y−b)²

The modified least squares method (Unbach and Jones) is convenient inthat there a simple close formed solution for a, b, and r.

$\hat{a} = \frac{{DC} - {BE}}{{AC} - B^{2}}$$\overset{\hat{}}{b} = \frac{{AE} - {BD}}{{AC} - B^{2}}$$\overset{\hat{}}{r} = {\frac{1}{n}{\sum\limits_{i = 1}^{n}\sqrt{\left( {x_{i} - \overset{\hat{}}{a}} \right)^{2} + \left( {y_{i} - \overset{\hat{}}{b}} \right)^{2}}}}$

The caret symbol over the variable “a” indicates an estimate of the truevalue. A, B, C, D, and E are summations of various products which arecalculated from the data. They are included herein for completeness asfollows:

$A:={{{{fpts} \cdot {\sum\limits_{i}^{fpts}\left( {Zout_{1,i}} \right)^{2}}} - \left( {\sum\limits_{i}^{fpts}\left( {Zout_{1,i}} \right)} \right)^{2}} = {5{\text{.463} \cdot 10^{10}}}}$$B:={{{{fpts}{\sum\limits_{i}^{fpts}\left( {Zou{t_{1,i} \cdot {Zout}_{2,i}}} \right)}} - \left( {\left( {\sum\limits_{i}^{fpts}\left( {Zout_{1,i}} \right)} \right) \cdot \left( {\sum\limits_{i}^{fpts}\left( {Zout_{2,i}} \right)} \right)} \right)} = {5{\text{.461} \cdot 10^{7}}}}$$C:={{{{fpts}\ {\sum\limits_{i}^{fpts}\left( {Zout_{2,i}} \right)^{2}}} - \left( {\sum\limits_{i}^{fpts}\left( {Zout_{2,i}} \right)} \right)^{2}} = {5{\text{.445} \cdot 10^{10}}}}$$D:={{0.5 \cdot \left( {{{fpts}{\sum\limits_{i}^{fpts}\left( {Zou{t_{1,i} \cdot \left( {Zout}_{2,i} \right)^{2}}} \right)}} - {\left( {\sum\limits_{i}^{fpts}\left( {Zout_{1,i}} \right)} \right) \cdot \left( {\sum\limits_{i}^{fpts}\left( {Zout_{2,i}} \right)^{2}} \right)} + {{fpts}{\sum\limits_{i}^{fpts}\left( {Zout}_{1,i}^{3} \right)}} - {\left( {\sum\limits_{i}^{fpts}\left( {Zout_{1,i}} \right)} \right) \cdot \left( {\sum\limits_{i}^{fpts}\left( {Zout_{1,i}} \right)^{2}} \right)}} \right)} = {5{\text{.529} \cdot 10^{3}}}}$$E:={{0.5 \cdot \left( {{{fpts}{\sum\limits_{i}^{fpts}\left( {Zou{t_{2,i} \cdot \left( {Zout}_{1,i} \right)^{2}}} \right)}} - {\left( {\sum\limits_{i}^{fpts}\left( {Zout_{2,i}} \right)} \right) \cdot \left( {\sum\limits_{i}^{fpts}\left( {Zout_{1,i}} \right)^{2}} \right)} + {{fpts}{\sum\limits_{i}^{fpts}\left( {Zout}_{2,i}^{3} \right)}} - {\left( {\sum\limits_{i}^{fpts}\left( {Zout_{2,i}} \right)} \right) \cdot \left( {\sum\limits_{i}^{fpts}\left( {Zout_{2,i}} \right)^{2}} \right)}} \right)} = {{- 5}{\text{.192} \cdot 10^{13}}}}$

Z1,i is a first vector of the real components referred to asconductance;

Z2,i is a second of the imaginary components referred to as susceptance;and

Z3,i is a third vector that represents the frequencies at whichadmittances are calculated.

This disclosure will work for ultrasonic systems and may possibly beapplied to electrosurgical systems, even though electrosurgical systemsdo not rely on a resonance.

FIGS. 60-64 illustrate images taken from an impedance analyzer showingimpedance/admittance circle plots for an ultrasonic device with the endeffector jaw in various open or closed configurations and loading. Thecircle plots in solid line depict impedance and the circle plots inbroken lines depict admittance, in accordance with at least one aspectof the present disclosure. By way of example, the impedance/admittancecircle plots are generated by connecting an ultrasonic device to animpedance analyzer. The display of the impedance analyzer is set tocomplex impedance and complex admittance, which can be selectable fromthe front panel of the impedance analyzer. An initial display may beobtained with the jaw of the ultrasonic end effector in an open positionand the ultrasonic device in an unloaded state, as described below inconnection with FIG. 60 , for example. The autoscale display function ofthe impedance analyzer may be used to generate both the compleximpedance and admittance circle plots. The same display is used forsubsequent runs of the ultrasonic device with different loadingconditions as shown in the subsequent FIGS. 60-64 . A LabVIEWapplication may be employed to upload the data files. In anothertechnique, the display images may be captured with a camera, such as asmartphone camera, like an iPhone or Android. As such, the image of thedisplay may include some “keystone-ing” and in general may not appear tobe parallel to the screen. Using this technique, the circle plot traceson the display will appear distorted in the captured image. With thisapproach, the material located in the jaws of the ultrasonic endeffector can be classified.

The complex impedance and complex admittance are just the reciprocal ofone another. No new information should be added by looking at both.Another consideration includes determining how sensitive the estimatesare to noise when using complex impedance or complex admittance.

In the examples illustrated in FIGS. 60-64 , the impedance analyzer isset up with a range to just capture the main resonance. By scanning overa wider range of frequencies more resonances may be encountered andmultiple circle plots may be formed. An equivalent circuit of anultrasonic transducer may be modeled by a first “motional” branch havinga serially connected inductance Ls, resistance Rs and capacitance Csthat define the electromechanical properties of the resonator, and asecond capacitive branch having a static capacitance C0. In theimpedance/admittance plots shown in FIGS. 60-64 that follow, the valuesof the components of the equivalent circuit are:

Ls=L1=1.1068 H

Rs=R1=311.352Ω

Cs=C1=7.43265 pF

C0=C0=3.64026 nF

The oscillator voltage applied to the ultrasonic transducer is 500 mVand the frequency is swept from 55 kHz to 56 kHz. The impedance (Z)scale is 200 Ω/div and the admittance (Y) scale is 500 μS/div.Measurements of values that may characterize the impedance (Z) andadmittance (Y) circle plots may be obtained at the locations on thecircle plots as indicated by an impedance cursor and an admittancecursor.

State of Jaw: Open with No Loading

FIG. 60 is a graphical display 132066 of an impedance analyzer showingcomplex impedance (Z)/admittance (Y) circle plots 132068, 132070 for anultrasonic device with the jaw open and no loading where a circle plot132068 in solid line depicts complex impedance and a circle plot 132070in broken line depicts complex admittance, in accordance with at leastone aspect of the present disclosure. The oscillator voltage applied tothe ultrasonic transducer is 500 mV and the frequency is swept from 55kHz to 56 kHz. The impedance (Z) scale is 200 Ω/div and the admittance(Y) scale is 500 μS/div. Measurements of values that may characterizethe complex impedance (Z) and admittance (Y) circle plots 132068, 132070may be obtained at locations on the circle plots 132068, 132070 asindicated by the impedance cursor 132072 and the admittance cursor132074. Thus, the impedance cursor 132072 is located at a portion of theimpedance circle plot 132068 that is equivalent to about 55.55 kHz, andthe admittance cursor 132074 is located at a portion of the admittancecircle plot 132070 that is equivalent to about 55.29 kHz. As depicted inFIG. 60 , the position of the impedance cursor 132072 corresponds tovalues of:

R=1.66026Ω

X=−697.309Ω

where R is the resistance (real value) and X is the reactance (imaginaryvalue). Similarly, the position of the admittance cursor 132074corresponds to values of:

G=64.0322 μS

B=1.63007 mS

where G is the conductance (real value) and B is susceptance (imaginaryvalue).

State of Jaw: Clamped on Dry Chamois

FIG. 61 is a graphical display 132076 of an impedance analyzer showingcomplex impedance (Z)/admittance (Y) circle plots 132078, 132080 for anultrasonic device with the jaw of the end effector clamped on drychamois where the impedance circle plot 132078 is shown in solid lineand the admittance circle plot 132080 is shown in broken line, inaccordance with at least one aspect of the present disclosure. Thevoltage applied to the ultrasonic transducer is 500 mV and the frequencyis swept from 55 kHz to 56 kHz. The impedance (Z) scale is 200 Ω/div andthe admittance (Y) scale is 500 μS/div.

Measurements of values that may characterize the complex impedance (Z)and admittance (Y) circle pots 132078, 132080 may be obtained atlocations on the circle plots 132078, 132080 as indicated by theimpedance cursor 132082 and the admittance cursor 132084. Thus, theimpedance cursor 132082 is located at a portion of the impedance circleplot 132078 that is equivalent to about 55.68 kHz, and the admittancecursor 132084 is located at a portion of the admittance circle plot132080 that is equivalent to about 55.29 kHz. As depicted in FIG. 61 ,the position of the impedance cursor 132082 corresponds to values of:

R=434.577Ω

X=−758.772 Ω

where R is the resistance (real value) and X is the reactance (imaginaryvalue). Similarly, the position of the admittance cursor 132084corresponds to values of:

G=85.1712 μS

B=1.49569 mS

where G is the conductance (real value) and B is susceptance (imaginaryvalue).

State of Jaw: Tip Clamped on Moist Chamois

FIG. 62 is a graphical display 132086 of an impedance analyzer showingcomplex impedance (Z)/admittance (Y) circle plots 132098, 132090 for anultrasonic device with the jaw tip clamped on moist chamois where theimpedance circle plot 132088 is shown in solid line and the admittancecircle plot 132090 is shown in broken line, in accordance with at leastone aspect of the present disclosure. The voltage applied to theultrasonic transducer is 500 mV and the frequency is swept from 55 kHzto 56 kHz. The impedance (Z) scale is 200 Ω/div and the admittance (Y)scale is 500 μS/div.

Measurements of values that may characterize the complex impedance (Z)and complex admittance (Y) circle plots 132088, 132090 may be obtainedat locations on the circle plots 132088, 132090 as indicated by theimpedance cursor 132092 and the admittance cursor 132094. Thus, theimpedance cursor 132092 is located at a portion of the impedance circleplot 132088 that is equivalent to about 55.68 kHz, and the admittancecursor 132094 is located at a portion of the admittance circle plot132090 that is equivalent to about 55.29 kHz. As depicted in FIG. 63 ,the impedance cursor 132092 corresponds to values of:

R=445.259 Ω

X=−750.082 Ω

where R is the resistance (real value) and X is the reactance (imaginaryvalue). Similarly, the admittance cursor 132094 corresponds to valuesof:

G=96.2179 μS

B=1.50236 mS

where G is the conductance (real value) and B is susceptance (imaginaryvalue).

State of Jaw: Fully Clamped on Moist Chamois

FIG. 63 is a graphical display 132096 of an impedance analyzer showingcomplex impedance (Z)/admittance (Y) circle plots 132098, 132100 for anultrasonic device with the jaw fully clamped on moist chamois where theimpedance circle plot 132098 is shown in solid line and the admittancecircle plot 132100 is shown in broken line, in accordance with at leastone aspect of the present disclosure. The voltage applied to theultrasonic transducer is 500 mV and the frequency is swept from 55 kHzto 56 kHz. The impedance (Z) scale is 200 Ω/div and the admittance (Y)scale is 500 μS/div.

Measurements of values that may characterize the impedance andadmittance circle plots 132098, 132100 may be obtained at locations onthe circle plots 132098, 1332100 as indicated by the impedance cursor13212 and admittance cursor 132104. Thus, the impedance cursor 132102 islocated at a portion of the impedance circle plot 132098 equivalent toabout 55.63 kHz, and the admittance cursor 132104 is located at aportion of the admittance circle plot 132100 equivalent to about 55.29kHz. As depicted in FIG. 63 , the impedance cursor 132102 corresponds tovalues of R, the resistance (real value, not shown), and X, thereactance (imaginary value, also not shown).

Similarly, the admittance cursor 132104 corresponds to values of:

G=137.272 μS

B=1.48481 mS

where G is the conductance (real value) and B is susceptance (imaginaryvalue).

State of Jaw: Open with No Loading

FIG. 64 is a graphical display 132106 of an impedance analyzer showingimpedance(Z)/admittance (Y) circle plots where frequency is swept from48 kHz to 62 kHz to capture multiple resonances of an ultrasonic devicewith the jaw open and no loading where the area designated by therectangle 132108 shown in broken line is to help see the impedancecircle plots 132110 a, 132110 b, 132110 c shown in solid line and theadmittance circle plots 132112 a, 132112 b, 132112 c, in accordance withat least one aspect of the present disclosure. The voltage applied tothe ultrasonic transducer is 500 mV and the frequency is swept from 48kHz to 62 kHz. The impedance (Z) scale is 500 Ω/div and the admittance(Y) scale is 500 μS/div.

Measurements of values that may characterize the impedance andadmittance circle plots 132110 a-c, 132112 a-c may be obtained atlocations on the impedance and admittance circle plots 132110 a-c,132112 a-c as indicated by the impedance cursor 132114 and theadmittance cursor 132116. Thus, the impedance cursor 132114 is locatedat a portion of the impedance circle plots 132110 a-c equivalent toabout 55.52 kHz, and the admittance cursor 132116 is located at aportion of the admittance circle plot 132112 a-c equivalent to about59.55 kHz. As depicted in FIG. 64 , the impedance cursor 132114corresponds to values of:

R=1.86163 kΩ

X=−536.229 Ω

where R is the resistance (real value) and X is the reactance (imaginaryvalue). Similarly, the admittance cursor 132116 corresponds to valuesof: G=649.956 μS B=2.51975 mS where G is the conductance (real value)and B is susceptance (imaginary value).

Because there are only 400 samples across the sweep range of theimpedance analyzer, there are only a few points about a resonance. So,the circle on the right side becomes choppy. But this is only due to theimpedance analyzer and the settings used to cover multiple resonances.

When multiple resonances are present, there is more information toimprove the classifier. The circle plots 132110 a-c, 132112 a-c fit canbe calculated for each as encountered to keep the algorithm runningfast. So once there is a cross of the complex admittance, which impliesa circle, during the sweep, a fit can be calculated.

Benefits include in-the-jaw classifier based on data and a well-knownmodel for ultrasonic systems. Count and characterizations of circles arewell known in vision systems. So data processing is readily available.For example, a closed form solution exists to calculate the radius andaxes' offsets for a circle. This technique can be relatively fast.

TABLE 2 is a list of symbols used for lumped parameter model of apiezoelectric transducer (from IEEE 177 Standard).

TABLE 2 References Symbols Meaning SI Units Equations Tables FiguresB_(p) Equivalent parallel susceptance of mho 2 vibrator C₀ Shunt(parallel) capacitance in the farad 2, 3, 4, 8 5 1, 4 equivalentelectric circuit C₁ Motional capacitance in the equivalent farad 2, 3,4, 6, 8, 9 5 1, 4 electric circuit f Frequency hertz 3 f_(a)Antiresonance frequency, zero hertz 2, 4 2, 3 susceptance f_(m)Frequency of maximum admittance hertz 2, 4 2, 3 (minimum impedance)f_(n) Frequency of minimum admittance hertz 2, 4 2, 3 (maximumimpedance) f_(p) Parallel resonance frequency hertz 2, 3 2, 4 2$({lossless}) = \frac{1}{2\pi\sqrt{L_{1}\frac{C_{1}C_{0}}{C_{1} + C_{0}}}}$f_(r) Resonance frequency, zero substance hertz 2, 4 2, 3 f_(B)${Motional}({series}){resonance}{frequency}\frac{1}{2}$ hertz 2, 3, 6,7, 9, 11a, 11b, 11c, 2, 4 2, 3, 6, 8 12, G_(p) Equivalent parallelconductance of  1 vibrator L₁ Motional inductance in the equivalenthenry 8, 9 1, 4, 5 electric circuit M${{Figure}{of}{merit}{of}a{vibrator}} = \frac{Q}{r}$ dimensionless 10,11a, 11b 3, 4, 5 $M = \frac{1}{\omega_{s}C_{0}R_{1}}$ Q${{Quality}{factor}Q} = {\frac{\omega_{s}L_{1}}{R_{1}} = {\frac{1}{\omega_{s}C_{1}R_{1}} = {rM}}}$dimensionless 12 3 6, 8 r${{Capacitance}{ratio}r} = \frac{C_{0}}{C_{1}}$ dimensionless 2, 3, 10,11 2, 3, 4, 5 8 R_(a) Impedance at zero phase angle near ohm 2, 3antiresonance R_(e) Equivalent series resistance of vibrator ohm 1, 2R_(r) Impedance at f_(r) zero phase angle ohm 2, 3 R₁ Motionalresistance in the equivalent ohm 4, 8, 10, 11a, 2, 5 1, 3, 4, 6, 7,electric circuit 11b, 11c, 12 8 X_(e) Equivalent series reactance ofvibrator ohm 1, 2 X₀ Reactance of shunt (parallel) ohm 1, 4, 5 5 3, 7capacitance at series resonance = $\frac{1}{\omega_{s}C_{0}}$ X₁Reactance of motional (series) arm of vibrator ohm 2 2 X 1 = ω L 1 - 1 ωC 1 Y Admittance of vibrator mho  1$Y = {{G_{p} +_{j}B_{p}} = \frac{1}{z}}$ Y_(m) Maximum admittance ofvibrator mho 3 Y_(n) Minimum admittance of vibrator mho 3 Z Impedance ofvibrator ohm  1 Z = R_(e) + _(j)X_(e) Z_(m) Minimum impedance ofvibrator ohm 3 Z_(n) Maximum impedance of vibrator ohm 3 Absolute valueof impedance of ohm 2 2 vibrator Z = {square root over (R_(e) ² +X_(e)²)} Absolute value of impedance at f_(m) ohm 2 (minimum impedance)Absolute value of impedance at f_(n) ohm 2 (maximum impedance) δNormalized damping factor δ = _(ω)C_(o)R₁ dimensionless  1 2 ΩNormalized frequency factor Ω = dimensionless  1 2$\frac{f^{2} - f_{s}^{2}}{f_{p}^{2} - f_{s}^{2}}$ ω Circular (angular)frequency hertz 2 ω = 2πf ω_(s) Circular frequency at motional hertzresonance ω_(s) = 2πf_(s)

TABLE 3 is a list of symbols for the transmission network (from IEEE 177Standard).

TABLE 3 References Symbols Meaning SI Units Equations Tables Figures bNormalized compensation factor 1 − dimensionless 4, 10 5$\frac{1}{4\pi^{2}f_{s}^{2}C_{0}L_{0}}$ B Normalized admittance factordimensionless 10 5 C Normalized admittance factor dimensionless 10 5C_(A-B) Stray capacitance between the farad terminals A-B (FIG. 4) C_(L)Load capacitance farad  6 4 C_(T) Shunt capacitance terminating farad 4,10 5 4 transmission circuit C_(L1) Load capacitance farad  7 C_(L2) Loadcapacitance farad  7 e₂ Output voltage of transmission volt 4 networkf_(mT) Frequency of maximum transmission hertz 10 F_(sL1) Motionalresonance frequency of hertz  7 combination of vibrator and C_(L1)F_(sL2) Motional resonance frequency of hertz  7 combination of vibratorand C_(L2) i₁ Input current to transmission network ampere 4 L₀Compensation inductance shunting henry 4 vibrator M_(T) Figure of meritof transmission dimensionless 4, 10 5 network termination =$\frac{1}{2_{\pi}f_{s}C_{T}R_{T}} = \frac{X_{T}}{R_{T}}$ R_(T) Shuntresistance termination of ohm 4, 11a, 11b, 5 4, 6, 7, 8 transmissionnetwork 11c, 12 R_(sL2) Standard resistor ohm 4, 5 5 7 S Detectorsensitivity smallest detectable dimensionless 12 6 currentchange/current x Normalized frequency factor x = dimensionless 12${\frac{f^{2}}{f_{s}^{2}} - 1} = \frac{\Omega}{r}$ X_(A-B) Reactance ofstray capacitance C_(A-B) ohm X_(T) Reactance of C_(T) at the motionalohm  4 5 resonance frequency $X_{T} = \frac{1}{2_{\pi}f_{s}C_{T}}$x_(mT) Normalized frequency factor at the dimensionless 5 frequency ofmaximum transmission ΔC_(L) ΔC_(L) = C_(L2) − C_(L1) farad 6, 7 Δf Δf₁ =f_(sL1) − f_(sL2) hertz 6, 7 6, 8 Δf₁ Δf₁ = f_(sL1) − f_(s) hertz 6, 7Δf₂ Δf₁ = f_(sL2) − f_(s) hertz 6, 7 *Refers to real roots; complexroots to be disregarded.

TABLE 4 is a list of solutions for various characteristic frequencies(from IEEE 177 Standard).

Solutions for the Various Characteristic Frequencies

TABLE 4 Characteristic Constituent Equasion for 57 IEEE FrequenciesMeaning Condition Frequency Root 14.S1¹ f_(m) Frequency of maximum = O−2δ²(Ω + r) − 2Ωr(1 − lower* f_(m) admittance (minimum Ω) − Ω² = 0impedance) f_(a) Motional (series) resonance X₁ = O Ω = 0 f_(a)frequency f_(r) Resonance frequency X_(e) = B_(p) = O Ω(1 − Ω) − δ² = 0lower f_(r) f_(a) Antiresonance requency X_(e) = B_(p) = O Ω(1 − Ω) − δ²= 0 upper f_(a) f_(p) Parallel resonance | Ω = 1 f_(p) frequency(lossless) = ∞ | R₁ = O f_(n) Frequency of minimum = O −2δ²(Ω + r) −2Ωr(1 − upper* f_(n) admittance (maximum Ω) − Ω² = 0 impedance) *Refersto real roots; complex roots to be disregarded

TABLE 5 is a list of losses of three classes of piezoelectric materials.

TABLE 5 Type of Piezoelectric Vibrator Q = Mr r Q^(r)/r minPiezoelectric Ceramics 90-500  2-40   200 Water-Soluble Piezoelectric 200-50,000 3-500  80 Crystals Quartz 10⁴-10⁷  100-50,000 2000 MinimumValues for the Ratio Q^(r)/r to be Expected for Various Types ofPiezoelectric Vibrators

TABLE 6 illustrates jaw conditions, estimated parameters of a circlebased on real time measurements of complex impedance/admittance, radius(re) and offsets (ae and be) of the circle represented by measuredvariables Re, Ge, Xe, Be, and parameters of a reference circle plots, asdescribed in FIGS. 60-64 , based on real time measurements of compleximpedance/admittance, radius (rr) and offsets (ar, br) of the referencecircle represented by reference variables Rref, Gref, Xref, Bref. Thesevalues are then compared with established values for given conditions.These conditions may be: 1) open with nothing in jaws, 2) tip bite 3)full bite and staple in jaws. The equivalent circuit of the ultrasonictransducer was modeled as follows and the frequency was swept from 55kHz to 56 kHz:

Ls=L1=1.1068H

Rs=R1=311.352Ω

Cs=C1=7.43265 pF and

C0=C0=3.64026 nF.

TABLE 6 Reference Circle Plot Reference Jaw Conditions R_(ref) (Ω)G_(ref) (μS) X_(ref) (Ω) B_(ef) (mS) Jaw open and no loading 1.6602664.0322 −697.309 1.63007 Jaw clamped on dry 434.577 85.1712 −758.7721.49569 chamois Jaw tip clamped on 445.259 96.2179 −750.082 1.50236moist chamois Jaw fully clamped on 137.272 1.48481 moist chamois

In use, the ultrasonic generator sweeps the frequency, records themeasured variables, and determines estimates Re, Ge, Xe, Be. Theseestimates are then compared to reference variables Rref, Gref, Xref,Bref stored in memory (e.g., stored in a look-up table) and determinesthe jaw conditions. The reference jaw conditions shown in TABLE 6 areexamples only. Additional or fewer reference jaw conditions may beclassified and stored in memory. These variables can be used to estimatethe radius and offsets of the impedance/admittance circle.

FIG. 65 is a logic flow diagram 132120 of a process depicting a controlprogram or a logic configuration to determine jaw conditions based onestimates of the radius (r) and offsets (a, b) of animpedance/admittance circle, in accordance with at least one aspect ofthe present disclosure. Initially a data base or lookup table ispopulated with reference values based on reference jaw conditions asdescribed in connection with FIGS. 60-64 and TABLE 6. A reference jawcondition is set and the frequency is swept from a value below resonanceto a value above resonance. The reference values Rref, Gref, Xref, Brefthat define the corresponding impedance/admittance circle plot arestored in a database or lookup table. During use, under control of acontrol program or logic configuration a processor or control circuit ofthe generator or instrument causes the frequency to sweep 132122 frombelow resonance to above resonance. The processor or control circuitmeasures and records 132124 (e.g., stores in memory) the variables Re,Ge, Xe, Be that define the corresponding impedance/admittance circleplot and compares 132126 them to the reference values Rref, Gref, Xref,Bref stored in the database or lookup table. The processor or controlcircuit determines 132128, e.g., estimates, the end effector jawconditions based on the results of the comparison.

Application of “Smart Blade” Technology

Current ultrasonic and/or combination ultrasonic/RF tissue treatmentconditions employ advanced tissue treatment algorithms with apre-determined current level for each step of the algorithm. Instead ofusing an advanced hemostasis tissue treatment algorithm with apre-determined current level for each step of the algorithm, theproposed advanced tissue treatment technique adjusts electrical currentdelivered to the ultrasonic transducer to drive the ultrasonic blade toa constant temperature using a frequency-temperature control system.

FIGS. 66A-66B are graphical representations of an advanced ultrasonictransducer current controlled hemostasis algorithm. For example, thetissue treatment process may start out by driving the ultrasonictransducer current to generate a high constant temperature for a firstpredetermined period T1. At the end of the first predetermined periodT1, the process drives the ultrasonic transducer current to generate alower constant temperature of the ultrasonic blade for a secondpredetermined period T2. The lower temperature of the ultrasonic blademay be suitable to achieve a tissue seal but not a tissue transection.Finally, the process drives the ultrasonic transducer current toincrease (ramps back up) the temperature of the ultrasonic blade to ahigher constant temperature for a third predetermined period T3. Thehigher temperature is high enough to complete the transection but islower than the melting point of the clamp arm pad. For example, thehigher ultrasonic blade temperature during the third predeterminedperiod T3 may be selected to be lower than the melting point of TEFLON,for example, which is a material commonly used for the clamp arm pad.

FIG. 66A is a graphical representation 132130 of percent of maximumcurrent delivered into an ultrasonic transducer as a function of time,in accordance with at least one aspect of the present disclosure. Thevertical axis represents percentage (%) of maximum current delivered toan ultrasonic transducer and the horizontal axis represents time (sec).The percentage of transducer current is set to a first percentage ofmaximum current X1% to raise the temperature of the ultrasonic bladeduring a first period T1. The percentage of transducer current is thenlowered to a second percentage of maximum current X2% over a secondperiod T2 to lower the blade temperature to a value that is suitable forsealing tissue but not for transecting tissue. The percentage oftransducer current is then increased to a third percentage of maximumcurrent X3% for a third period T3, to raise the blade temperature to avalue that is suitable for transecting tissue but is lower than themelting point of the clamp arm pad (e.g., TEFLON). According to theprocess graphically depicted in FIG. 66A, the same percentage ofultrasonic transducer current profile may be used for all tissue types,loading conditions, etc.

FIG. 66B is a graphical representation 132140 of ultrasonic bladetemperature as a function of time and tissue type, in accordance with atleast one aspect of the present disclosure. The vertical axis representstemperature (° F.) of the ultrasonic blade and the horizontal axisrepresents time (sec). This technique may be combined with impedancespectroscopy to detect tissue of various thicknesses. Such as forexample, thick tissue versus thin tissue, located in the jaws of theultrasonic end effector. Once the tissue thickness is detected, theultrasonic blade temperature may be controlled to accommodate differentlevels of energy delivery as may be needed across a range of tissuetypes and adjust the advanced hemostasis algorithm in real-time. Oncethe tissue type is detected or determined, the ultrasonic bladetemperature is set to a nominal temperature Temp₁ by controlling thedriving current into the ultrasonic transducer. The temperature of theultrasonic blade is set to a first temperature Temp₁, which may beraised (+) or lowered (−) based on tissue type over a first period T1.The ultrasonic blade temperature is then lowered to a second temperatureTemp₂ over a second period T2 to lower the blade temperature to a valuethat is suitable for sealing tissue but not for transecting tissue. Thesecond temperature Temp₂, also may be raised (+) or lowered (−) based onthe detected tissue type. The ultrasonic blade temperature is thenincreased to a third temperature Temp₃ over a third period T3 to a valuethat is suitable for transecting tissue but that is lower than themelting point temperature Tw of the clamp jaw pad material. According tothe process depicted in FIG. 66B, the ultrasonic blade temperature canbe varied based on tissue types, loading conditions, etc. In addition,the ultrasonic blade temperature versus time profile can be varied byvarying the periods T1-T3. Finally, the ultrasonic blade temperatureversus time profile can be varied by varying both the temperature of theultrasonic blade and the time periods T1-T3.

In one example, for audible surgeon feedback, tones can be tied toachieving a certain temperature threshold. This would improveconsistency in advanced hemostasis transection times and hemostasisacross a range of tissue types.

FIG. 67 is a logic flow diagram 132150 of a process depicting a controlprogram or a logic configuration to control the temperature of anultrasonic blade based on tissue type, in accordance with at least oneaspect of the present disclosure. The tissue type may be determined132152 using the techniques described in FIGS. 19-21 under the headingESTIMATING THE STATE OF THE JAW (PAD BURN THROUGH, STAPLES, BROKENBLADE, BONE IN JAW, TISSUE IN JAW and/or FIGS. 22-30 under the headingSTATE OF JAW CLASSIFIER BASED ON MODEL and/or techniques for estimatingthe temperature of the ultrasonic blade are described in related U.S.Provisional Patent Application No. 62/640,417, titled TEMPERATURECONTROL IN ULTRASONIC DEVICE AND CONTROL SYSTEM THEREFOR, to Nott et al,which is incorporated herein by reference in its entirety. According tothe process, a control circuit in the generator or instrument determinesthe tissue type and sets the initial temperature of the ultrasonic bladeto a nominal temperature by controlling the driving current into theultrasonic transducer. The control circuit raises (+) or lowers (−) thetemperature of the ultrasonic blade based on tissue type over a firstperiod T1. The control circuit then lowers the temperature of theultrasonic blade to a second temperature over a second period T2 tolower the blade temperature to a value that is suitable for sealingtissue but not for transecting tissue. The control circuit raises (+) orlowers (−) the second temperature based on the detected tissue type. Thecontrol circuit increases the temperature of the ultrasonic blade to athird temperature over a third period T3, to a value that is suitablefor transecting tissue but is lower than the melting point of the clampjaw pad material (e.g., TEFLON).

Smart Blade And Power Pulsing

During surgery with an ultrasonic shears device the power delivered tothe tissue is set at a predetermined level. That predetermined level isused to transect the tissue throughout the transection procedure.Certain tissues may seal better or cut better/faster if the powerdelivered varies throughout the transection procedure. A solution isneeded to vary the power delivered to the tissue through the bladeduring the transection process. In various aspects, the tissue type andchanges to the tissue during the transection process may be determinedusing the techniques described in FIGS. 19-21 under the headingESTIMATING THE STATE OF THE JAW (PAD BURN THROUGH, STAPLES, BROKENBLADE, BONE IN JAW, TISSUE IN JAW and/or FIGS. 22-30 under the headingSTATE OF JAW CLASSIFIER BASED ON MODEL and/or techniques for estimatingthe temperature of the ultrasonic blade are described in related U.S.Provisional Patent Application No. 62/640,417, titled TEMPERATURECONTROL IN ULTRASONIC DEVICE AND CONTROL SYSTEM THEREFOR, to Nott et al,which is incorporated herein by reference in its entirety.

One solution that provides better ultrasonic transection employs theimpedance feedback of the ultrasonic blade. As previously discussed, theimpedance of the ultrasonic blade is related to the impedance of theelectromechanical ultrasonic system and may be determined by measuringthe phase angle between the voltage and current signals applied to theultrasonic transducer as described herein. This technique may beemployed to measure the magnitude and phase of the impedance of theultrasonic transducer. The impedance of the ultrasonic transducer may beemployed to profile factors that may be influencing the ultrasonic bladeduring use (e.g., force, temperature, vibration, force over time, etc.).This information may be employed to affect the power delivered to theultrasonic blade during the transection process.

FIG. 68 is a logic flow diagram 132170 of a process depicting a controlprogram or a logic configuration to monitor the impedance of anultrasonic transducer to profile an ultrasonic blade and deliver powerto the ultrasonic blade on the profile according to one aspect of theresent disclosure. According to the process, a control circuitdetermines 132172 (e.g., measures) the impedance (Z) of the ultrasonictransducer during a tissue transection process. The control circuitanalyzes and profiles 132174 the ultrasonic blade right after the tissueis fully clamped in jaw of the end effector of the ultrasonic devicebased on the determined 132172 impedance (Z). The control circuitadjusts 132176 a power output level based on the profile (e.g., highpower for dense tissue low power for thin tissue) of the ultrasonicblade. The control circuit controls the generator to momentarily drivethe ultrasonic transducer and the ultrasonic blade and then stops. Thecontrol circuit again determines 132172 the impedance (Z) of theultrasonic blade and profiles 132174 the ultrasonic blade based on thedetermined 132172 impedance (Z). The control circuit controls thegenerator to adjust the output power level or keep it the same based onthe profile of the ultrasonic blade. The control circuit again controlsthe generator to momentarily drive the ultrasonic transducer and theultrasonic blade and then stops. The process repeats and determines132172 the impedance (Z), profiles 132174 the ultrasonic blade, andadjusts 132176 the power level until the impedance profile detected isthat of the clam arm pad and then adjusts the power to prevent the clamparm pad from melting.

The process discussed in connection with FIG. 68 allows the ultrasonictransducer power level to be adjusted on the fly as the tissue changesfrom being heated and cut. Accordingly, if the tissue is initially toughand then weakens or if different layers of tissue are encountered duringthe transection process, the power level can be optimally adjusted tomatch the profile of the ultrasonic blade. This method could eliminatethe need for the user to set the power level. The ultrasonic devicewould adapt and choose the right power level based on current tissueconditions and transection process.

This technique provides intelligent control for power level settingbased on tissue feedback. This technique may eliminate the need forpower settings on the generator and may lead to faster transectiontimes. In one aspect, in an ultrasonic transection medical deviceincluding a jaw with an ultrasonic blade, the impedance of theultrasonically driven blade is used to profile the ultrasonic bladecharacteristics (force, heat, vibration, etc.) and that profile is usedto influence the power output of the transducer during the transectionprocess. Power may be pulsed on and off so that the tissue changes canbe read for feedback in between pulses to adjust the power during thetransection process.

FIGS. 69A-69D is a series of graphical representations of the impedanceof an ultrasonic transducer to profile an ultrasonic blade and deliverpower to the ultrasonic blade based on the profile, in accordance withat least one aspect of the present disclosure. FIG. 69A is a graphicalrepresentation 132180 of ultrasonic transducer impedance versus time.The generator control circuit reads the initial impedance Z1 which isbased on the contents of the jaw and applies a pulsed power P1 to theultrasonic transducer as shown in FIG. 69B, which is a graphicaldepiction 132182 of pulsed power versus time. FIG. 69C is a graphicalrepresentation 132184 of a new impedance Z2 versus time. The controlcircuit of the generator reads the new impedance Z2 and applies pulsedpower P2 to the ultrasonic transducer to meet the new tissue conditionas plotted in FIG. 69D, which is a graphical representation 132186 ofpulsed power P2 versus time.

Adjustment of Complex Impedance to Compensate for Lost Power in anArticulating Ultrasonic Device

FIG. 70 is a system 132190 for adjusting complex impedance of theultrasonic transducer 132192 to compensate for power lost when theultrasonic blade 132194 is articulated, in accordance with at least oneaspect of the present disclosure. The performance of an articulatableultrasonic blade 132194 is inconsistent throughout the full articulationangle θ from A-B. For example, power is lost when the ultrasonic blade132194 is articulated. Knowing the articulation angle θ that theultrasonic blade 132194 is at, the generator 132196 or the surgicalinstrument 132199 can adjust the complex impedance (Z) to compensate forthe power lost when the ultrasonic blade 132194 is articulated. Also, byanalyzing the performance of the ultrasonic blade 132194 through itsfull articulation angle θ, the generator 132196 can execute an algorithmto adjust the complex impedance (Z) to compensate for power loss.

Adjusting complex impedance of the ultrasonic transducer 132192 tocompensate for power lost when the ultrasonic blade 132194 may employthe techniques described in FIGS. 19-21 under the heading ESTIMATING THESTATE OF THE JAW (PAD BURN THROUGH, STAPLES, BROKEN BLADE, BONE IN JAW,TISSUE IN JAW and/or FIGS. 22-30 under the heading STATE OF JAWCLASSIFIER BASED ON MODEL and/or techniques for estimating thetemperature of the ultrasonic blade are described in related U.S.Provisional Patent Application No. 62/640,417, titled TEMPERATURECONTROL IN ULTRASONIC DEVICE AND CONTROL SYSTEM THEREFOR, to Nott et al,which is incorporated herein by reference in its entirety.

These techniques may be employed to determine the articulation angle θof the ultrasonic blade 132194 by sweeping through a range ofarticulation angles θ from A−B at a predetermined angular increment. Ateach angular increment, activating the ultrasonic transducer 132192 ateither a therapeutic or non-therapeutic energy level, measuring thecomplex impedance (Z) of the ultrasonic transducer 132192, recording aset of complex impedance (Z) measurements, generating reference compleximpedance characteristic patterns or a training data sets S as afunction of articulation angle θ, and storing the reference compleximpedance characteristic patterns or a training data sets S in a memoryor database that is accessible by the ultrasonic instrument 132199during a surgical procedure. During a surgical procedure, the ultrasonicinstrument 132199 can determine articulation angle θ by comparing realtime complex impedance (Z) measurements of the ultrasonic transducer132192 with the reference complex impedance characteristic patterns or atraining data sets S.

Articulatable ultrasonic waveguides 132198 are described in U.S. Pat.No. 9,095,367 titled Flexible Harmonic Waveguides/Blades For SurgicalInstruments, which is incorporated herein by reference. See FIGS. 47-66Band associated description. Measurement of articulation angle isdescribed in U.S. Pat. No. 9,808,244 titled Sensor Arrangements ForAbsolute Positioning System For Surgical Instruments, which isincorporated herein by reference. See FIGS. 193-196 and associateddescription.

FIG. 71 is a logic flow diagram 132200 of a process depicting a controlprogram or a logic configuration to compensate output power as afunction of articulation angle, in accordance with at least one aspectof the present disclosure. Accordingly, in conjunction with FIG. 70 ,during use, a control circuit of the generator 132196 or instrumentdetermines 132202 the articulation angle θ of the ultrasonic blade132194. The control circuit adjusts 132204 the complex impedance (Z) tocompensate for power lost as a function of articulation angle θ. Thecontrol circuit applies 132206 the output power of the generator 132196applied to the ultrasonic transducer 132192 based on the articulationangle θ of the ultrasonic blade 132194.

Using Spectroscopy to Determine Device Use State in Combo Instrument

FIG. 72 is a system 132210 for measuring complex impedance (Z) of anultrasonic transducer 132212 in real time to determine action beingperformed by an ultrasonic blade 132214, in accordance with at least oneaspect of the present disclosure. Current surgical instruments includethree functions (seal+cut, seal only, and spot coagulation). Thesefunctions can be executed by activating two buttons. It would be usefulif the surgeon only had to press one button and could receive either theseal only or spot coagulation algorithm based on the desired action tobe performed. Ultrasonic spectroscopy can be used to measure the compleximpedance (Z) of the ultrasonic blade 132214 in real time. The real timemeasurements can be compared to predefined data to determine whichaction is being performed. The different complex impedance (Z) patternsbetween spot coagulation and seal only enable the generator 132216 todetermine which action is being performed and to execute the appropriatealgorithm.

Measuring complex impedance (Z) of an ultrasonic transducer 132212 inreal time to determine action being performed by an ultrasonic blade132214 may employ the techniques described in FIGS. 19-21 under theheading ESTIMATING THE STATE OF THE JAW (PAD BURN THROUGH, STAPLES,BROKEN BLADE, BONE IN JAW, TISSUE IN JAW and/or FIGS. 22-30 under theheading STATE OF JAW CLASSIFIER BASED ON MODEL and/or techniques forestimating the temperature of the ultrasonic blade are described inrelated U.S. Provisional Patent Application No. 62/640,417, titledTEMPERATURE CONTROL IN ULTRASONIC DEVICE AND CONTROL SYSTEM THEREFOR, toNott et al, which is incorporated herein by reference in its entirety.

TABLE 7 is a chart of ultrasonic blade action and corresponding compleximpedance. This information is stored in a memory lookup table ordatabase.

TABLE 7 Ultrasonic Blade Action Impedance (Z) Seal only Z1 Spotcoagulation Z2

FIG. 73 is a logic flow diagram 132220 of a process depicting a controlprogram or a logic configuration to determine action being performed byan ultrasonic blade 132214 (FIG. 72 ) based on the complex impedancepattern, in accordance with at least one aspect of the presentdisclosure. Prior to implementing the process described in FIG. 73 andin conjunction with FIG. 72 , a database or memory lookup table ispopulated with data of ultrasonic blade 132214 actions and observedcomplex impedances (Z) associated with the ultrasonic blade 132214actions. The database or lookup table can be accessed by the ultrasonicinstrument 132218 or generator 132216 while executing the ultrasonicblade 132214 action. Accordingly, during a hemostasis procedure, acontrol circuit of the generator 132216 or instrument 13218 determines132222 the complex impedance (Z) of the ultrasonic blade 132214. Thecontrol circuit compares 132224 the measured complex impedance (Z) tostored values of complex impedance patterns associated with ultrasonicblade 132214 functions. The control circuit controls the generator132216 to apply 132226 an output power algorithm to the ultrasonictransducer 132212 based on the comparison.

Vessel Sensing for Adaptive Advanced Hemostasis

In various aspects, the present disclosure provides adaptive vesselsealing modes. In one aspect, the ultrasonic instrument can deliverultrasonic energy uniquely for veins as opposed to arteries.

In another aspect, the present disclosure provides a technique foridentifying the jaw contents of an ultrasonic device. Using thisapproach, a vessel clamped in the jaw is identified as either a vein oran artery, which can be characterized as differences in vessel wall andpressure. Knowing that a vessel is a vein or an artery can be used toactivate a unique advanced hemostasis cycle for each type. A veinrequires more time and lower temperature due to the thinner vesselwalls, so an advanced hemostasis cycle will include lower current andlonger time in the vessel sealing portion of the cycle.

FIG. 74 is a logic flow diagram 132230 depicting a control program or alogic configuration of an adaptive process for identifying a hemostasisvessel, in accordance with at least one aspect of the presentdisclosure. In accordance with the process, a control circuit of thegenerator or instrument senses 132232 the vessel located in the jaw ofthe ultrasonic device using any of the smart blade algorithm techniquesfor estimating or classifying the state of the jaw of an ultrasonicdevice described in connection with FIGS. 19-21 under the headingESTIMATING THE STATE OF THE JAW (PAD BURN THROUGH, STAPLES, BROKENBLADE, BONE IN JAW, TISSUE IN JAW and/or FIGS. 22-30 under the headingSTATE OF JAW CLASSIFIER BASED ON MODEL and/or techniques for estimatingthe temperature of the ultrasonic blade are described in related U.S.Provisional Patent Application No. 62/640,417, titled TEMPERATURECONTROL IN ULTRASONIC DEVICE AND CONTROL SYSTEM THEREFOR, to Nott et al,which is incorporated herein by reference in its entirety. When a veinis sensed 132234 or an artery is sensed 132236, the control circuitreceives a command for sealing either a vein or an artery and activates132238 an advanced hemostasis algorithm based on the type of vesselsensed. In one aspect, the command may be originated by a user from abutton located on the instrument to activate the appropriate advancedhemostasis algorithm. In other aspects, the command may be originatedautomatically based on tissue characterization algorithms.

When a vein is sensed 132234, the control circuit executes 132240 afirst algorithm that can seal slower at a lower power level and lowerultrasonic blade temperature. Accordingly, to treat a vein, the controlcircuit controls the generator to output a lower power P1 and activatesthe generator for a longer time T1.

When an artery is sensed 132236, the control circuit executes 132242 asecond algorithm that can seal faster at a higher power level and higherultrasonic blade temperature. Accordingly, to treat an artery, thecontrol circuit controls the generator to output higher power P2 andactivates the generator for a shorter time T2.

FIG. 75 is a graphical representation 132250 of ultrasonic transducercurrent profiles as a function of time for vein and artery vessel types,in accordance with at least one aspect of the present disclosure. Thevertical axis is generator output current (I) delivered to theultrasonic transducer and the horizontal axis is time (sec). Withreference also to FIG. 74 , the first curve 132252 represents a vein andis treated with lower power (P1 at I1) and longer period (T1) and thesecond curve 132254 represents an artery and is treated with higherpower (P2 at I2) applied for a shorter period (T2) relative to the firstcurve 132252.

In another aspect, the present disclosure provides a technique fordelivering ultrasonic transducer current (I) in a feedback control loopto achieve a targeted frequency which is associated with a desiredultrasonic blade temperature. When sealing a vein, for example, thefeedback control loop will drive to a higher targeted frequency whichcorresponds to a cooler ultrasonic blade temperature that is suitable(and may be ideal) for sealing the vein. An artery would be driven to aslightly lower frequency target associated with a hotter ultrasonicblade temperature.

FIG. 76 is a logic flow diagram 132260 depicting a control program or alogic configuration of an adaptive process for identifying a hemostasisvessel, in accordance with at least one aspect of the presentdisclosure. In accordance with the process, a control circuit of thegenerator or instrument senses 132262 the vessel in the jaw using any ofthe smart blade algorithm techniques for estimating or classifying thestate of the jaw of an ultrasonic device described in connection withFIGS. 19-21 under the heading ESTIMATING THE STATE OF THE JAW (PAD BURNTHROUGH, STAPLES, BROKEN BLADE, BONE IN JAW, TISSUE IN JAW and/or FIGS.22-30 under the heading STATE OF JAW CLASSIFIER BASED ON MODEL and/ortechniques for estimating the temperature of the ultrasonic blade aredescribed in related U.S. Provisional Patent Application No. 62/640,417,titled TEMPERATURE CONTROL IN ULTRASONIC DEVICE AND CONTROL SYSTEMTHEREFOR, to Nott et al, which is incorporated herein by reference inits entirety.

When a vein is sensed 132264, the control circuit executes a firstalgorithm to supply 132268 current to the ultrasonic transducer toachieve a targeted seal temperature for a vein. A feedback control loopestimates the temperature of the ultrasonic blade and adjusts thecurrent delivered to the ultrasonic transducer to control thetemperature of the ultrasonic blade. When an artery is sensed 132266,the control circuit executes a second algorithm to supply 132269 currentto the ultrasonic transducer to achieve a targeted seal temperature foran artery. A feedback control loop estimates the temperature of theultrasonic blade and adjusts the current delivered to the ultrasonictransducer to control the temperature of the ultrasonic blade.

FIG. 77 is a graphical representation 132270 of ultrasonic transducerfrequency profiles as a function of time for vein and artery vesseltypes, in accordance with at least one aspect of the present disclosure.The vertical axis represents the frequency (kHz) of the signal appliedto the ultrasonic transducer and the horizontal axis represents time(sec). The first curve 132272 represents a vein. A vein requires acooler ultrasonic blade temperature to effect a seal. The firstalgorithm controls the temperature of the ultrasonic blade by settingthe frequency applied to the ultrasonic transducer to a higher frequencyand controls current delivered to the ultrasonic transducer to maintainthe set frequency. The second curve 132274 represents an artery. Anartery requires a hotter ultrasonic blade temperature to effect a seal.The second algorithm controls the temperature of the ultrasonic blade bysetting the frequency applied to the ultrasonic transducer to a lowerfrequency and controls current delivered to the ultrasonic transducer tomaintain the set frequency.

Calcified Vessel Identification

In various aspects, the present disclosure provides various techniquesfor improving hemostasis when sealing calcified vessels and to addresschallenges in sealing calcified vessels. In one aspect, the ultrasonicinstrument is configured to manage sealing of calcified vessels withintelligence. In one aspect, the jaw contents may be identifiedidentification using smart blade algorithm techniques for estimating orclassifying the state of the jaw of an ultrasonic device described inconnection with FIGS. 19-21 under the heading ESTIMATING THE STATE OFTHE JAW (PAD BURN THROUGH, STAPLES, BROKEN BLADE, BONE IN JAW, TISSUE INJAW and/or FIGS. 22-30 under the heading STATE OF JAW CLASSIFIER BASEDON MODEL and/or techniques for estimating the temperature of theultrasonic blade are described in related U.S. Provisional PatentApplication No. 62/640,417, titled TEMPERATURE CONTROL IN ULTRASONICDEVICE AND CONTROL SYSTEM THEREFOR, to Nott et al, which is incorporatedherein by reference in its entirety. Accordingly, these techniques maybe employed to identify a calcified vessel when clamped in the jaws ofthe ultrasonic instrument.

Three possible scenarios are disclosed. In one aspect, the user isprompted with a warning from the generator that the jaws are clamping ona calcified vessel and the instrument will not fire. In another aspect,the instruments prompts a user that they the jaws have clamped acalcified vessel and it will not allow the instrument to fire until aminimum amount of compression time (say 10-15 seconds) has elapsed. Thisadditional time allows the calcification/plaque to migrate away from thetransection side and improve hemostasis of the seal. In a third aspect,upon grasping a calcified vessel and pressing the activation button, theinstrument employs an internal motor to displace the spring stack anadditional amount in order to deliver slightly more clamp force andbetter compression of the calcified vessel.

FIG. 78 is a logic flow diagram 132280 depicting a control program or alogic configuration of a process for identifying a calcified vessel, inaccordance with at least one aspect of the present disclosure. Accordingto the process, a control circuit of the generator or instrumentidentifies a vessel located in the jaw of the ultrasonic device when thejaw clamps 132282 on the vessel. When the control circuit identifies132284 a calcified vessel, the control circuit sends 132286 a warningmessage that can be perceived by the user. The message containsinformation to notify the user that a calcified vessel has beendetected. The control circuit then prompts 132288 to maintaincompression on the calcified vessel for a predetermined waiting periodT1 (e.g., x-seconds). This will allow the calcification to migrate awayfrom the jaws. At the expiration of the compression waiting period T1,the control circuit enables 132290 the activation of the ultrasonicgenerator. When the control circuit identifies 132292 a “normal (e.g.,not calcified) vessel, the control circuit enables 132294 normalactivation of the ultrasonic device. Accordingly, the ultrasonic devicecan execute one or more hemostasis algorithms as described herein.

FIG. 79 is a logic flow diagram 132300 depicting a control program or alogic configuration of a process for identifying a calcified vessel, inaccordance with at least one aspect of the present disclosure. Accordingto the process, a control circuit of the generator or instrumentidentifies a vessel located in the jaw of the ultrasonic device when thejaw clamps 132302 on the vessel. When the control circuit identifies132304 a calcified vessel, the control circuit sends 132306 a warningmessage that can be perceived by the user that a calcified vessel wasdetected. The control circuit disables 132308 or alternatively does notenable activation of the ultrasonic device. When the control circuitidentifies 132310 a “normal” vessel (e.g., not calcified), the controlcircuit enables 132312 normal activation of the ultrasonic device.Accordingly, the ultrasonic device can execute one or more hemostasisalgorithms as described herein.

FIG. 80 is a logic flow diagram 132320 depicting a control program or alogic configuration of a process for identifying a calcified vessel, inaccordance with at least one aspect of the present disclosure. Accordingto the process, a control circuit of the generator or instrumentidentifies a vessel located in the jaw of the ultrasonic device when thejaw clamps 132322 on the vessel. When the control circuit identifies132324 a calcified vessel, the control circuit sends 132326 a warningmessage that can be perceived by the user that a calcified vessel wasdetected. The control circuit increases 132328 the jaw clamp force witha motor in order to achieve better compression of the calcified vessel.The control circuit then enables 132330 activation of the ultrasonicenergy after a clamp force adjustment. When the control circuitidentifies 132332 a “normal” vessel (e.g., not calcified), the controlcircuit enables 132334 normal activation of the ultrasonic device.Accordingly, the ultrasonic device can execute one or more hemostasisalgorithms as described herein.

Detection of Large Vessels During Parenchymal Dissection Using a SmartBlade

During liver resection procedures, surgeons risk cutting large vesselsbecause they are buried inside the parenchyma that is being dissected,and thus cannot be seen. FIGS. 81-86 of this disclosure outlines anapplication for a “smart blade” (e.g., an ultrasonic blade with feedbackto provide jaw content identification) that can detect the differencebetween parenchymal tissue, and large vessels within the parenchymaltissue by using the magnitude and phase of the impedance measurementsover a swept frequency range. During a parenchymal dissection procedure,vessels may be detected using smart blade algorithm techniques forestimating or classifying the state of the jaw of an ultrasonic devicedescribed in connection with FIGS. 19-21 under the heading ESTIMATINGTHE STATE OF THE JAW (PAD BURN THROUGH, STAPLES, BROKEN BLADE, BONE INJAW, TISSUE IN JAW and/or FIGS. 22-30 under the heading STATE OF JAWCLASSIFIER BASED ON MODEL and/or techniques for estimating thetemperature of the ultrasonic blade are described in related U.S.Provisional Patent Application No. 62/640,417, titled TEMPERATURECONTROL IN ULTRASONIC DEVICE AND CONTROL SYSTEM THEREFOR, to Nott et al,which is incorporated herein by reference in its entirety.

During liver resection and dissection procedures of other vascularparenchymal tissues, the surgeon cannot see vessels that are embeddedwithin the parenchyma along the dissection plane. This can causesurgeons to cut large vessels without sealing, resulting in excessivebleeding that causes blood loss to the patient and stress for thesurgeon. FIGS. 81-86 describe a solution that offers a method ofdetecting large vessels embedded in parenchymal tissues without the needto visualize the large vessels using a smart ultrasonic bladeapplication.

The ultrasonic devices described herein may be employed to accomplishfollowing vessel detection prior to initiating a liver resection anddissection procedure. A control circuit of the generator or theultrasonic device initiates a frequency sweep from below resonance toabove resonance of the electromechanical ultrasonic system to enablemeasurements of the magnitude and phase of the impedance. The resultsare plotted on a 3D curve as described in connection with FIGS. 19-21 .The resulting 3D curve will have a particular form when the ultrasonicblade is in contact with parenchymal tissue and will have other formswhen the ultrasonic blade contacts tissue other than parenchymal tissue,as discussed below.

A different 3D curve is generated by the frequency sweep when theultrasonic blade is contacting a large vessel. When the ultrasonic bladecontacts a vessel, the control circuit compares the test frequency sweepof the new (vessel) curve with the frequency sweep of the old(parenchyma) curve and identifies the new (vessel) curve as beingdifferent from the old (parenchyma) curve. Based on the comparisonresults, the control circuit enables an action to be taken by theultrasonic device to prevent cutting into the large vessel, and toinform the surgeon that a large vessel is located on or is in contactwith the ultrasonic blade.

The various actions that can be taken by the ultrasonic device includewithout limitation, change the therapeutic output of the device toprevent cutting of the vessel or change the tone from the generator toinform the surgeon that a vessel has been detected, or a combinationthereof.

Alternatively, various aspects of this technique may be applied todetect blood if a vessel had been cut, allowing the surgeon to quicklyseal the vessel, even without seeing the cut vessel.

FIG. 81 is a diagram 132340 of a liver resection 132350 with vessels132354 (FIG. 82 ) embedded in parenchymal tissue, in accordance with atleast one aspect of the present disclosure. An ultrasonic instrument132342 including an ultrasonic blade 132344 and clamp arm 132346 isshown cutting into a liver 132348 to create a resection 132350. Theultrasonic instrument 132342 is coupled to a generator 132352 thatcontrols the delivery of energy to the ultrasonic instrument 132342.Either the generator 132252 or the ultrasonic instrument 132342, orboth, include a control circuit configured to execute the advanced smartblade algorithms discussed herein.

FIG. 82 is a diagram 132356 of an ultrasonic blade 132344 in the processof cutting through parenchyma without contacting a vessel 132354embedded in the liver 132348, in accordance with at least one aspect ofthe present disclosure. During the resection process the control circuitmonitors the impedance, magnitude, and phase of the signals driving theultrasonic transducer to assess the state of the jaw, e.g. the state ofthe ultrasonic blade 132344, as depicted in FIGS. 85A and 85B.Accordingly, as the ultrasonic blade 132344 resects liver 132348 theultrasonic transducer produces a first response and when the ultrasonicblade 132344 contacts the embedded vessel 132354 the ultrasonictransducer produces a second response, which is associated with theembedded vessel 132354 type as described herein in connection with FIGS.54-86 .

FIGS. 83A and 83B are graphical representations 132360 of ultrasonictransducer impedance magnitude/phase with the parenchyma curves 132362shown in bold line, in accordance with at least one aspect of thepresent disclosure. FIG. 83A is a three-dimensional plot and FIG. 83B isa two-dimensional plot. These curves are generated in accordance withFIGS. 19-21 , for example, and associated description under the headingESTIMATING THE STATE OF THE JAW (PAD BURN THROUGH, STAPLES, BROKENBLADE, BONE IN JAW, TISSUE IN JAW. Alternatively, techniques forestimating or classifying the state of the jaw of an ultrasonic devicedescribed in connection with FIGS. 22-30 under the heading STATE OF JAWCLASSIFIER BASED ON MODEL and/or techniques for estimating thetemperature of the ultrasonic blade are described in related U.S.Provisional Patent Application No. 62/640,417, titled TEMPERATURECONTROL IN ULTRASONIC DEVICE AND CONTROL SYSTEM THEREFOR may beemployed.

FIG. 84 is a diagram 132364 of an ultrasonic blade 132344 in the processof cutting through parenchyma and contacting a vessel 132354 embedded inthe liver 132348, in accordance with at least one aspect of the presentdisclosure. As the ultrasonic blade 132344 transects the liver 132348parenchyma tissue, the ultrasonic blade 132344 contacts the vessel132354 at a location 132366 and thus shifts the resonant frequency ofthe ultrasonic transducer as depicted in FIGS. 85A and 85B. The controlcircuit monitors the impedance, magnitude, and phase of the signalsdriving the ultrasonic transducer to assess the state of the jaw, e.g.the state of the ultrasonic blade 132344 while contacting the vessel132354, as depicted in FIGS. 85A and 85B.

FIGS. 85A and 85B are graphical representations 132370 ultrasonictransducer impedance magnitude/phase with large vessel curves 132372shown in bold line, in accordance with at least one aspect of thepresent disclosure. FIG. 85A is a three-dimensional plot and FIG. 85B isa two-dimensional plot. These curves are generated in accordance withFIGS. 19-21 and associated description under the heading ESTIMATING THESTATE OF THE JAW (PAD BURN THROUGH, STAPLES, BROKEN BLADE, BONE IN JAW,TISSUE IN JAW. Alternatively, techniques for estimating or classifyingthe state of the jaw of an ultrasonic device described in connectionwith FIGS. 22-30 under the heading STATE OF JAW CLASSIFIER BASED ONMODEL and/or techniques for estimating the temperature of the ultrasonicblade are described in related U.S. Provisional Patent Application No.62/640,417, titled TEMPERATURE CONTROL IN ULTRASONIC DEVICE AND CONTROLSYSTEM THEREFOR may be employed.

FIG. 86 is a logic flow diagram 132380 depicting a control program or alogic configuration of a process for treating tissue in parenchyma whena vessel is detected as shown in FIGS. 84-85B, in accordance with atleast one aspect of the present disclosure. According to the process,using the techniques for estimating or classifying the state of the jawof an ultrasonic device described in connection with FIGS. 19-21 underthe heading ESTIMATING THE STATE OF THE JAW (PAD BURN THROUGH, STAPLES,BROKEN BLADE, BONE IN JAW, TISSUE IN JAW and/or FIGS. 22-30 under theheading STATE OF JAW CLASSIFIER BASED ON MODEL and/or techniques forestimating the temperature of the ultrasonic blade are described inrelated U.S. Provisional Patent Application No. 62/640,417, titledTEMPERATURE CONTROL IN ULTRASONIC DEVICE AND CONTROL SYSTEM THEREFOR,the control circuit determines if a vessel 132354 is located is incontact with the ultrasonic blade 132344. If the control circuit detectsa vessel 132382, the control circuit stops 132384 the cutting energy,switches 132386 to a lower power level, and sends 132388 a warningmessage or alert to the user. For example, the control circuit lowersthe excitation voltage/current signal power to a level below what isrequired for cutting a vessel. The warning message or alert may includeemitting a light, emitting a sounding, activating a buzzer, and thelike. If a vessel 132354 is not detected, the resection processcontinues 132390.

Smart Ultrasonic Blade Application for Reusable and Disposable Devices

The smart blade algorithm uses spectroscopy to identify the status of anultrasonic blade. This capability can be applied to reusable anddisposable devices with detachable clamp arms to distinguish if thedisposable portion of the device has been installed correctly. Thestatus of the ultrasonic blade may be determined using smart bladealgorithm techniques for estimating or classifying the state of the jawof an ultrasonic device described in connection with FIGS. 19-21 underthe heading ESTIMATING THE STATE OF THE JAW (PAD BURN THROUGH, STAPLES,BROKEN BLADE, BONE IN JAW, TISSUE IN JAW and/or FIGS. 22-30 under theheading STATE OF JAW CLASSIFIER BASED ON MODEL and/or techniques forestimating the temperature of the ultrasonic blade are described inrelated U.S. Provisional Patent Application No. 62/640,417, titledTEMPERATURE CONTROL IN ULTRASONIC DEVICE AND CONTROL SYSTEM THEREFOR, toNott et al, which is incorporated herein by reference in its entirety.

The smart blade algorithm techniques described herein can be employed toidentify the status of components of reusable and disposable devices. Inone aspect, the status of the ultrasonic blade may be determined todistinguish if disposable portions of reusable and disposable deviceshave been installed correctly or incorrectly.

FIGS. 87 and 88 is a reusable and disposable ultrasonic device 132400configured to identify the status of the ultrasonic blade 132402 anddetermine the clocked status of the clamp arm 132404 to determinewhether a portion of the reusable and disposable ultrasonic device132400 has been installed correctly, in accordance with at least oneaspect of the present disclosure. FIG. 88 is an end effector 132406portion of the reusable and disposable ultrasonic device 132400 shown inFIG. 87 . Similarities and differences between the spectroscopysignatures can be used to determine whether the reusable and disposablecomponents of the reusable and disposable ultrasonic device 132400 havebeen installed correctly or incorrectly.

The reusable and disposable ultrasonic device 132400 shown in FIGS. 87and 88 includes a reusable handle 132408 and a disposable ultrasonicwaveguide/blade 132402. Prior to use, a proximal end 132410 of thedisposable ultrasonic waveguide/blade 132402 is inserted 132414 into adistal opening 132412 of the reusable handle 132408 and twisted orrotated clockwise 132416 to lock the disposable ultrasonicwaveguide/blade 132402 into the handle 132408 as shown in FIG. 87 . Ifthe disposable ultrasonic waveguide/blade 132402 is not fully inserted132414 and/or fully rotated clockwise 132416, the reusable anddisposable ultrasonic device 132400 will not operate properly. Forexample, improper insertion 132414 and rotation 132416 of the disposableultrasonic waveguide/blade 132402 will result in poor mechanicalcoupling of the disposable ultrasonic waveguide/blade 132402 and willproduce a different spectroscopy signature. Therefore, the smart bladealgorithm techniques described herein can be used to determine if thedisposable portion of the reusable and disposable ultrasonic device132400 has been inserted 132414 and rotated 132416 completely.

In another misaligned configuration, if the clamp arm 132404 shown inFIG. 88 is clocked (rotated) relative to the ultrasonic blade 132402,the orientation of the ultrasonic blade 132402 relative to the clamp arm132404 will be out of alignment. This also will produce a differentspectroscopy signature when the reusable and disposable ultrasonicdevice 132400 is actuated and/or clamped. Therefore, the smart bladealgorithm techniques described herein can be used to determine if thedisposable portion of the reusable and disposable ultrasonic device132400 has been properly clocked (rotated) relative to the clamp arm132404.

In another aspect, the smart blade algorithm techniques described hereincan be used to determine if a disposable portion of the reusable anddisposable ultrasonic device 132400 has been pushed in or inserted132414 all the way into the reusable portion 132408. This may beapplicable to the reusable and disposable ultrasonic device 132400 inFIG. 89 below where a reusable portion such as the handle 132408, forexample, is 132414 inserted into a disposable portion, such as theultrasonic blade 132402, for example, prior to operation.

FIG. 89 is a reusable and disposable ultrasonic device 132420 configuredto identify the status of the ultrasonic blade 132422 and determinewhether the clamp arm 132424 is not completely distal to determinewhether a disposable portion 132426 of the reusable and disposableultrasonic device 132420 has been installed correctly, in accordancewith at least one aspect of the present disclosure. If the clamp arm isnot installed completely distal there will be a different spectroscopysignature when the device is clamped. In another aspect, if thedisposable portion 132426 is not installed completely distal on thereusable component 132428, the ultrasonic blade 132422 spectroscopysignature will be different when clamped into position. Therefore, thesmart blade algorithm techniques described herein can be used todetermine if the disposable portion 132426 of the reusable anddisposable ultrasonic device 132420 has been fully and properly coupledto the reusable portion 132428.

FIG. 90 is a logic flow diagram 132430 depicting a control program or alogic configuration to identify the status of components of reusable anddisposable ultrasonic devices, in accordance with at least one aspect ofthe present disclosure. According to the process depicted by the logicflow diagram 132430, a control circuit of the generator or instrumentexecutes a smart blade algorithm technique and determines 132432 thespectroscopy signature of assembled reusable and disposable ultrasonicdevices 132400, 132420 (FIGS. 88 and 89 ) comprising reusable anddisposable components. The control circuit compares 132434 the measuredspectroscopy signature to a reference spectroscopy signature, where thereference spectroscopy signature is associated with a properly assembledreusable and disposable ultrasonic device 132400, 132420 and is storedin a database or memory of the generator or instrument. When the controlcircuit determines 132436 that the measured spectroscopy signaturediffers from the reference spectroscopy signature, the control circuitdisables 132438 the operation of the reusable and disposable ultrasonicdevice 132400, 132420 and generates 132440 a warning that can beperceived by the user. The waning may include activating a light sourcesound source, or vibration source. When the measured spectroscopysignature is the same or substantially similar to the referencespectroscopy signature, the control circuit enables 132442 the normaloperation of the reusable and disposable ultrasonic device 132400,132420.

Live Time Tissue Classification Using Electrical Parameters Sealingwithout Cutting, RF/Ultrasonic Combination Technology. TailoredAlgorithms

In one aspect, the present disclosure provides an algorithm forclassifying tissue into groups. The ability to classify tissue in livetime will allow for tailoring algorithms to a specific tissue group. Thetailored algorithms can optimize seal times and hemostasis across alltissue types. In one aspect, the present disclosure provides a sealingalgorithm to provide hemostasis needed for large vessels and quicklyseal smaller structures that do not need extended energy activation. Theability to classify these distinct tissue types allows for optimizedalgorithms for each group in live time.

In this aspect, during the first 0.75 seconds of the activation, 3 RFelectrical parameters are used in a plot to classify tissue intodistinct groups. These electrical parameters are: Initial RF impedance(taken at 0.15 seconds), Minimum RF impedance in first 0.75 seconds, andthe amount of time the RF impedance slope is −0 in milliseconds. Aplurality of other times that these data points are taken could beimplemented. All of this data is collected in a set amount of time, andthen using a Support Vector Machine (SVM) or another classificationalgorithm the tissue can be classified into a distinct group in livetime. Each tissue group would have an algorithm specific to it thatwould be implemented for the remainder of the activation. Types of SVM'sinclude linear, polynomial, and radial basis function (RBF).

FIG. 91 is a three-dimensional graphical representation 132450 ofepidermal growth factor (EGF) radio frequency (RF) tissue impedanceclassification, in accordance with at least one aspect of the presentdisclosure. The x-axis represents the minimum RF impedance (Zmin) of thetissue, the y-axis represents initial RF impedance (Zinit) of thetissue, and the z-axis represents the amount of time that the derivativeof the RF impedance (Z) of the tissue is approximately 0. FIG. 91 showsa grouping of large vessels 132452, e.g., carotids—thick tissue, andsmall vessels 132454, e.g., thyros—thin tissue, when using the three RFparameters of Initial RF impedance, Minimum RF Impedance, and the amountof time the derivative (slope) of the RF impedance is approximately zerowithin the first 0.75 seconds of activation. A distinction of thisclassification method is that the tissue type can be classified in a setamount of time. The advantage to this method is a tissue specificalgorithm can be chosen towards the beginning of the activation, sospecialized tissue treatment can begin before the exit out of the RFbathtub. It will be appreciated that in the context of tissue impedanceunder the influence of RF energy a bathtub region is a curve wherein thetissue impedance drops after the initial application of RF energy andstabilizes until the tissue begins to dry out. Thereafter the tissueimpedance increases. Thus, the impedance versus time curve resembles theshape of a “bathtub.”

This data was used to train and test a Support Vector Machine to groupthick and thin tissue, and accurately classified 94% of the time.

In one aspect, the present disclosure provides a device comprising onecombo RF/Ultrasonic algorithm that is used for all tissue types and ithas been identified that seal speeds for thin tissues are longer thannecessary, however larger vessels and thicker structures could benefitfrom an extended activation. This classification scheme will enable thecombo RF/ultrasonic device to seal small structures with optimal speedsand burst pressures, and to seal larger structures to ensure maximumhemostasis is achieved.

FIG. 92 is a three-dimensional graphical representation 132460 ofepidermal growth factor (EGF) radio frequency (RF) tissue impedanceanalysis, in accordance with at least one aspect of the presentdisclosure. The x-axis represents the minimum RF impedance (Zmin) of thetissue, the y-axis represents the initial RF impedance (Zinit) of thetissue, and the z-axis represents the amount of time that the derivativeof the RF impedance (Z) of the tissue is approximately 0. To determineif this classification model of thick tissue 132462 versus thin tissue132464 was robust to different tissue types, data was added for variousbenchtop tissue types, and the tissue grouped into two distinct groups.It is possible to separate this data into a plurality of groups if it isdeemed beneficial or necessary. The different thick tissue 132462 typesinclude, for example, carotid, jejunum, mesentery, jugular, and livertissue. The different thin tissue 132464 types include, for example,thyro and thyro vein.

Fine Dissection Mode for Tissue Classification Tissue Classification toEnable Multiple Modes to Account for Different Surgical Techniques

In one aspect, the present disclosure provides an algorithm forclassifying tissue into groups and tailoring an algorithm to classifyspecific tissue classes in live time. This disclosure builds upon thefoundation and details of another potential benefit to classifyingtissue as previously discussed herein under the heading LIVE TIME TISSUECLASSIFICATION USING ELECTRICAL PARAMETERS.

FIG. 93 is a graphical representation 132470 of carotid techniquesensitivity where the time that the RF impedance (Z) derivative isapproximately 0 is plotted as a function of initial RF impedance, inaccordance with at least one aspect of the present disclosure. It isknown that different surgical techniques exist in different regions ofthe world, and vary widely from surgeon to surgeon. For this reason, atechnique mode may be provided on the generator to enable more efficientenergy delivery based upon the user's specific surgical technique suchas, for example, a tip bite of tissue versus a full bite of tissue. Atip bite refers to the end effector of a surgical device grasping tissueat the tip only. A full bite refers to the end effector of a surgicaldevice grasping tissue within the entire end effector. The generator maybe configured to detect if a user is consistently operating with a tipbite of tissue or a full bite of tissue. As shown in FIG. 93 initial RFimpedance data was measured and plotted for tip bites as Group 1 132472and full bites as Group 2 132474. As shown, Group 1 132472 tip bites oftissue register an initial RF impedance Z_(init) of less than 250 Ohmsand Group 2 132474 full bites of tissue register an initial impedanceZ_(Init) between 250 Ohms and 500 Ohms, the maximum RF tissue impedanceZ_(Max). Upon detecting whether the user grasps a tip bite of tissue ora full bite of tissue, the algorithm can suggest a predetermineddissection mode. For example, for a tip bite of tissue the algorithm maysuggest a fine dissection mode to the user or this option may beselected before a procedure. For example, for a full bite of tissue thealgorithm may suggest a course dissection mode to the user or thisoption may be selected before a procedure. In fine dissection mode, thealgorithm may be tailored to optimize energy delivery for this surgicaltechnique by lowering the ultrasonic displacement to protect the clamparm pad from burning through. Also it is known that tip biting has agreater amount of RF noise, causing longer seal times, and greatervariation in seal performance. Fine dissection mode for tip biting coldhave an algorithm tailored to having a lower RF termination impedanceand/or different filtering signal to increase accuracy of energydelivery.

A technique sensitivity analysis was conducted as part of thedevelopment work for classification. The testing was conducted bytransecting 3-7 mm vessels in a benchtop setting using differentsurgical techniques such as full bite transection with and withouttension, and tip bite transection with and without tension. The initialRF impedance, and the time the slope the RF impedance=0 were allexamined as significant factors in classifying the tissue into groups.

It was determined that surgical techniques could be grouped into 3distinct groups based on the initial RF impedance Z_(Init). Initial RFimpedance Z_(Init) generally ranging between 0-100 ohms indicatesoperating in a bloody field. Initial RF impedance Z_(Init) generallyranging between 100-300 ohms indicates operating under normalconditions, and initial RF impedance Z_(Init) greater than 300 ohmsindicates abuse condition especially where tensions is present.

Temperature Inference

FIGS. 94A-94B are graphical representations 133000, 133010 of compleximpedance spectra of the same ultrasonic device with a cold (roomtemperature) and hot ultrasonic blade, in accordance with at least oneaspect of the present disclosure. As used herein, a cold ultrasonicblade refers to an ultrasonic blade at room temperature and a hotultrasonic blade refers to an ultrasonic blade after it is frictionallyheated in use. FIG. 94A is a graphical representation 133000 ofimpedance phase angle φ as a function of resonant frequency f_(o) of thesame ultrasonic device with a cold and hot ultrasonic blade and FIG. 94Bis a graphical representation 133010 of impedance magnitude |Z| as afunction of resonant frequency f_(o) of the same ultrasonic device witha cold and hot ultrasonic blade. The impedance phase angle φ andimpedance magnitude |Z| are at a minimum at the resonant frequencyf_(o).

The ultrasonic transducer impedance Z_(g)(t) can be measured as theratio of the drive signal generator voltage V_(g)(t) and currentI_(g)(t) drive signals:

${Z_{g}(t)} = \frac{V_{g}(t)}{I_{g}(t)}$

As shown in FIG. 94A, when the ultrasonic blade is cold, e.g., at roomtemperature and not frictionally heated, the electromechanical resonantfrequency f_(o) of the ultrasonic device is approximately 55,500 Hz andthe excitation frequency of the ultrasonic transducer is set to 55,500Hz. Thus, when the ultrasonic transducer is excited at theelectromechanical resonant frequency f_(o) and the ultrasonic blade iscold the phase angle φ is at minimum or approximately 0 Rad as indicatedby the cold blade plot 133002. As shown in FIG. 94B, when the ultrasonicblade is cold and the ultrasonic transducer is excited at theelectromechanical resonant frequency f_(o), the impedance magnitude |Z|is 800Ω, e.g., the impedance magnitude |Z| is at a minimum impedance,and the drive signal amplitude is at a maximum due to the seriesresonance equivalent circuit of the ultrasonic electromechanical systemas depicted in FIG. 6 .

With reference now back to FIGS. 94A and 94B, when the ultrasonictransducer is driven by generator voltage V_(g)(t) and generator currentI_(g)(t) signals at the electromechanical resonant frequency f_(o) of55,500 Hz, the phase angle φ between the generator voltage V_(g)(t) andgenerator current I_(g)(t) signals is zero, the impedance magnitude |Z|is at a minimum impedance, e.g., 800Ω, and the signal amplitude is at apeak or maximum due to the series resonance equivalent circuit of theultrasonic electromechanical system. As the temperature of theultrasonic blade increases, due to frictional heat generated in use, theelectromechanical resonant frequency f_(o)′ of the ultrasonic devicedecreases. Since the ultrasonic transducer is still driven by generatorvoltage V_(g)(t) and generator current I_(g)(t) signals at the previous(cold blade) electromechanical resonant frequency f_(o) of 55,500 Hz,the ultrasonic device operates off-resonance f_(o)′ causing a shift inthe phase angle φ between the generator voltage V_(g)(t) and generatorcurrent I_(g)(t) signals. There is also an increase in impedancemagnitude |Z| and a drop in peak magnitude of the drive signal relativeto the previous (cold blade) electromechanical resonant frequency of55,500 Hz. Accordingly, the temperature of the ultrasonic blade may beinferred by measuring the phase angle φ between the generator voltageV_(g)(t) and the generator current I_(g)(t) signals as theelectromechanical resonant frequency f_(o) changes due to the changes intemperature of the ultrasonic blade.

As previously described, an electromechanical ultrasonic system includesan ultrasonic transducer, a waveguide, and an ultrasonic blade. Aspreviously discussed, the ultrasonic transducer may be modeled as anequivalent series resonant circuit (see FIG. 6 ) comprising first branchhaving a static capacitance and a second “motional” branch having aserially connected inductance, resistance and capacitance that definethe electromechanical properties of a resonator. The electromechanicalultrasonic system has an initial electromechanical resonant frequencydefined by the physical properties of the ultrasonic transducer, thewaveguide, and the ultrasonic blade. The ultrasonic transducer isexcited by an alternating voltage V_(g)(t) and current I_(g)(t) signalat a frequency equal to the electromechanical resonant frequency, e.g.,the resonant frequency of the electromechanical ultrasonic system. Whenthe electromechanical ultrasonic system is excited at the resonantfrequency, the phase angle φ between the voltage V_(g)(t) and currentI_(g)(t) signals is zero.

Stated in another way, at resonance, the analogous inductive impedanceof the electromechanical ultrasonic system is equal to the analogouscapacitive impedance of the electromechanical ultrasonic system. As theultrasonic blade heats up, for example due to frictional engagement withtissue, the compliance of the ultrasonic blade (modeled as an analogouscapacitance) causes the resonant frequency of the electromechanicalultrasonic system to shift. In the present example, the resonantfrequency of the electromechanical ultrasonic system decreases as thetemperature of the ultrasonic blade increases. Thus, the analogousinductive impedance of the electromechanical ultrasonic system is nolonger equal to the analogous capacitive impedance of theelectromechanical ultrasonic system causing a mismatch between the drivefrequency and the new resonant frequency of the electromechanicalultrasonic system. Thus, with a hot ultrasonic blade, theelectromechanical ultrasonic system operates “off-resonance.” Themismatch between the drive frequency and the resonant frequency ismanifested as a phase angle φ between the voltage V_(g)(t) and currentI_(g)(t) signals applied to the ultrasonic transducer.

As previously discussed, the generator electronics can easily monitorthe phase angle φ between the voltage V_(g)(t) and current I_(g)(t)signals applied to the ultrasonic transducer. The phase angle φ may bedetermined through Fourier analysis, weighted least-squares estimation,Kalman filtering, space-vector-based techniques, zero-crossing method,Lissajous figures, three-voltmeter method, crossed-coil method, vectorvoltmeter and vector impedance methods, phase standard instruments,phase-locked loops, among other techniques previously described. Thegenerator can continuously monitor the phase angle φ and adjust thedrive frequency until the phase angle φ goes to zero. At this point, thenew drive frequency is equal to the new resonant frequency of theelectromechanical ultrasonic system. The change in phase angle φ and/orgenerator drive frequency can be used as an indirect or inferredmeasurement of the temperature of the ultrasonic blade.

A variety of techniques are available to estimate temperature from thedata in these spectra. Most notably, a time variant, non-linear set ofstate space equations can be employed to model the dynamic relationshipbetween the temperature of the ultrasonic blade and the measuredimpedance:

${Z_{g}(t)} = \frac{V_{g}(t)}{I_{g}(t)}$

across a range of generator drive frequencies, where the range ofgenerator drive frequencies is specific to device model.

Methods of Temperature Estimation

One aspect of estimating or inferring the temperature of an ultrasonicblade may include three steps. First, define a state space model oftemperature and frequency that is time and energy dependent. To modeltemperature as a function of frequency content, a set of non-linearstate space equations are used to model the relationship between theelectromechanical resonant frequency and the temperature of theultrasonic blade. Second, apply a Kalman filter to improve the accuracyof the temperature estimator and state space model over time. Third, astate estimator is provided in the feedback loop of the Kalman filter tocontrol the power applied to the ultrasonic transducer, and hence theultrasonic blade, to regulate the temperature of the ultrasonic blade.The three steps are described hereinbelow.

Step 1

The first step is to define a state space model of temperature andfrequency that is time and energy dependent. To model temperature as afunction of frequency content, a set of non-linear state space equationsare used to model the relationship between the electromechanicalresonant frequency and the temperature of the ultrasonic blade. In oneaspect, the state space model is defined by:

$\begin{bmatrix}\overset{.}{F_{n}} \\\overset{˙}{T}\end{bmatrix} = {f\left( {t,{T(t)},{F_{n}(t)},{E(t)}} \right)}$$\overset{.}{y} = {h\left( {t,{T(t)},{F_{n}(t)},{E(t)}} \right)}$

The state space model represents the rate of change of the naturalfrequency of the electromechanical ultrasonic system {dot over (F)}_(n)and the rate of change of the temperature {dot over (T)} of theultrasonic blade with respect to natural frequency F_(n)(t), temperatureT(t), energy E(t), and time t. {dot over (y)} represents theobservability of variables that are measurable and observable such asthe natural frequency F_(n)(t) of the electromechanical ultrasonicsystem, the temperature T(t) of the ultrasonic blade, the energy E(t)applied to the ultrasonic blade, and time t. The temperature T(t) of theultrasonic blade is observable as an estimate.

Step 2

The second step is to apply a Kalman filter to improve temperatureestimator and state space model. FIG. 95 is a diagram of a Kalman filter133020 to improve the temperature estimator and state space model basedon impedance according to the equation:

${Z_{g}(t)} = \frac{V_{g}(t)}{I_{g}(t)}$

which represents the impedance across an ultrasonic transducer measuredat a variety of frequencies, in accordance with at least one aspect ofthe present disclosure.

The Kalman filter 133020 may be employed to improve the performance ofthe temperature estimate and allows for the augmentation of externalsensors, models, or prior information to improve temperature predictionin the midst of noisy data. The Kalman filter 133020 includes aregulator 133022 and a plant 133024. In control theory a plant 133024 isthe combination of process and actuator. A plant 133024 may be referredto with a transfer function which indicates the relation between aninput signal and the output signal of a system. The regulator 133022includes a state estimator 133026 and a controller K 133028. The stateregulator 133026 includes a feedback loop 133030. The state regulator133026 receives y, the output of the plant 133024, as an input and afeedback variable u. The state estimator 133026 is an internal feedbacksystem that converges to the true value of the state of the system. Theoutput of the state estimator 133026 is {circumflex over (x)}, the fullfeedback control variable including F_(n)(t) of the electromechanicalultrasonic system, the estimate of the temperature T(t) of theultrasonic blade, the energy E(t) applied to the ultrasonic blade, thephase angle φ, and time t. The input into the controller K 133028 is{dot over (x)} and the output of the controller K 133028 u is fed backto the state estimator 133026 and t of the plant 133024.

Kalman filtering, also known as linear quadratic estimation (LQE), is analgorithm that uses a series of measurements observed over time,containing statistical noise and other inaccuracies, and producesestimates of unknown variables that tend to be more accurate than thosebased on a single measurement alone, by estimating a joint probabilitydistribution over the variables for each timeframe and thus calculatingthe maximum likelihood estimate of actual measurements. The algorithmworks in a two-step process. In a prediction step, the Kalman filter133020 produces estimates of the current state variables, along withtheir uncertainties. Once the outcome of the next measurement(necessarily corrupted with some amount of error, including randomnoise) is observed, these estimates are updated using a weightedaverage, with more weight being given to estimates with highercertainty. The algorithm is recursive and can run in real time, usingonly the present input measurements and the previously calculated stateand its uncertainty matrix; no additional past information is required.

The Kalman filter 133020 uses a dynamics model of the electromechanicalultrasonic system, known control inputs to that system, and multiplesequential measurements (observations) of the natural frequency andphase angle of the applied signals (e.g., magnitude and phase of theelectrical impedance of the ultrasonic transducer) to the ultrasonictransducer to form an estimate of the varying quantities of theelectromechanical ultrasonic system (its state) to predict thetemperature of the ultrasonic blade portion of the electromechanicalultrasonic system that is better than an estimate obtained using onlyone measurement alone. As such, the Kalman filter 133020 is an algorithmthat includes sensor and data fusion to provide the maximum likelihoodestimate of the temperature of the ultrasonic blade.

The Kalman filter 133020 deals effectively with uncertainty due to noisymeasurements of the applied signals to the ultrasonic transducer tomeasure the natural frequency and phase shift data and also dealseffectively with uncertainty due to random external factors. The Kalmanfilter 133020 produces an estimate of the state of the electromechanicalultrasonic system as an average of the predicted state of the system andof the new measurement using a weighted average. Weighted values providebetter (i.e., smaller) estimated uncertainty and are more “trustworthy”than unweighted values The weights may be calculated from thecovariance, a measure of the estimated uncertainty of the prediction ofthe system's state. The result of the weighted average is a new stateestimate that lies between the predicted and measured state, and has abetter estimated uncertainty than either alone. This process is repeatedat every time step, with the new estimate and its covariance informingthe prediction used in the following iteration. This recursive nature ofthe Kalman filter 133020 requires only the last “best guess,” ratherthan the entire history, of the state of the electromechanicalultrasonic system to calculate a new state.

The relative certainty of the measurements and current state estimate isan important consideration, and it is common to discuss the response ofthe filter in terms of the gain K of the Kalman filter 133020. TheKalman gain K is the relative weight given to the measurements andcurrent state estimate, and can be “tuned” to achieve particularperformance. With a high gain K, the Kalman filter 133020 places moreweight on the most recent measurements, and thus follows them moreresponsively. With a low gain K, the Kalman filter 133020 follows themodel predictions more closely. At the extremes, a high gain close toone will result in a more jumpy estimated trajectory, while low gainclose to zero will smooth out noise but decrease the responsiveness.

When performing the actual calculations for the Kalman filter 133020 (asdiscussed below), the state estimate and covariances are coded intomatrices to handle the multiple dimensions involved in a single set ofcalculations. This allows for a representation of linear relationshipsbetween different state variables (such as position, velocity, andacceleration) in any of the transition models or covariances. Using aKalman filter 133020 does not assume that the errors are Gaussian.However, the Kalman filter 133020 yields the exact conditionalprobability estimate in the special case that all errors areGaussian-distributed.

Step 3

The third step uses a state estimator 133026 in the feedback loop 133032of the Kalman filter 133020 for control of power applied to theultrasonic transducer, and hence the ultrasonic blade, to regulate thetemperature of the ultrasonic blade.

FIG. 96 is a graphical depiction 133040 of three probabilitydistributions employed by the state estimator 133026 of the Kalmanfilter 133020 shown in FIG. 95 to maximize estimates, in accordance withat least one aspect of the present disclosure. The probabilitydistributions include the prior probability distribution 133042, theprediction (state) probability distribution 133044, and the observationprobability distribution 133046. The three probability distributions133042, 133044, 1330467 are used in feedback control of power applied toan ultrasonic transducer to regulate temperature based on impedanceacross the ultrasonic transducer measured at a variety of frequencies,in accordance with at least one aspect of the present disclosure. Theestimator used in feedback control of power applied to an ultrasonictransducer to regulate temperature based on impedance is defined by theexpression:

${Z_{g}(t)} = \frac{V_{g}(t)}{I_{g}(t)}$

which is the impedance across the ultrasonic transducer measured at avariety of frequencies, in accordance with at least one aspect of thepresent disclosure.

The prior probability distribution 133042 includes a state variancedefined by the expression:

(σ_(k) ⁻)²=σ_(k-1) ²+σ_(P) _(k) ²

The state variance (σ_(k) ⁻) is used to predict the next state of thesystem, which is represented as the prediction (state) probabilitydistribution 133044. The observation probability distribution 133046 isthe probability distribution of the actual observation of the state ofthe system where the observation variance σ_(m) is used to define thegain, which is defined by the following expression:

$K = \frac{\left( \sigma_{k}^{-} \right)^{2}}{\left( \sigma_{k}^{-} \right)^{2} + \sigma_{m}^{2}}$

Feedback Control

Power input is decreased to ensure that the temperature (as estimated bythe state estimator and of the Kalman filter) is controlled.

In one aspect, the initial proof of concept assumed a static, linearrelationship between the natural frequency of the electromechanicalultrasonic system and the temperature of the ultrasonic blade. Byreducing the power as a function of the natural frequency of theelectromechanical ultrasonic system (i.e., regulating temperature withfeedback control), the temperature of the ultrasonic blade tip could becontrolled directly. In this example, the temperature of the distal tipof the ultrasonic blade can be controlled to not exceed the meltingpoint of the Teflon pad.

FIG. 97A is a graphical representation 133050 of temperature versus timeof an ultrasonic device without temperature feedback control.Temperature (° C.) of the ultrasonic blade is shown along the verticalaxis and time (sec) is shown along the horizontal axis. The test wasconducted with a chamois located in the jaws of the ultrasonic device.One jaw is the ultrasonic blade and the other jaw is the clamp arm witha TEFLON pad. The ultrasonic blade was excited at the resonant frequencywhile in frictional engagement with the chamois clamped between theultrasonic blade and the clamp arm. Over time, the temperature (° C.) ofthe ultrasonic blade increases due to the frictional engagement with thechamois. Over time, the temperature profile 133052 of the ultrasonicblade increases until the chamois sample is cut after about 19.5 secondsat a temperature of 220° C. as indicated at point 133054. Withouttemperature feedback control, after cutting the chamois sample, thetemperature of the ultrasonic blade increases to a temperature wellabove the melting point of TEFLON ˜380° C. up to ˜490° C. At point133056 the temperature of the ultrasonic blade reaches a maximumtemperature of 490° C. until the TEFLON pad is completely melted. Thetemperature of the ultrasonic blade drops slightly from the peaktemperature at point 133056 after the pad is completely gone.

FIG. 97B is a plot of temperature versus time of an ultrasonic devicewith temperature feedback control, in accordance with at least oneaspect of the present disclosure. Temperature (° C.) of the ultrasonicblade is shown along the vertical axis and the time (sec) is shown alongthe horizontal axis. The test was conducted with a chamois samplelocated in the jaws of the ultrasonic device. One jaw is the ultrasonicblade and the other jaw is the clamp arm with a TEFLON pad. Theultrasonic blade was excited at the resonant frequency while infrictional engagement with the chamois clamped between the ultrasonicblade and the clamp arm pad. Over time, the temperature profile 133062of the ultrasonic blade increases until the chamois sample is cut afterabout 23 seconds at a temperature of 220° C. as indicated at point133064. With temperature feedback control, the temperature of theultrasonic blade increases up to a maximum temperature of about 380° C.,just below the melting point of TEFLON, as indicated at point 133066 andthen is lowered to an average of about 330° C. as indicated generally atregion 133068, thus preventing the TEFLON pad from melting.

Controlled Thermal Management (CTM) for Pad Protection

In one aspect, the present disclosure provides a controlled thermalmanagement (CTM) algorithm to regulate temperature with feedbackcontrol. The output of the feedback control can be used to prevent theultrasonic end effector clamp arm pad from burning through, which is nota desirable effect for ultrasonic surgical instruments. As previouslydiscussed, in general, pad burn through is caused by the continuedapplication of ultrasonic energy to an ultrasonic blade in contact withthe pad after tissue grasped in the end effector has been transected.

The CTM algorithm leverages the fact that the resonant frequency of anultrasonic blade, general made of titanium, varies in proportion totemperature. As the temperature increases, the modulus of elasticity ofthe ultrasonic blade decreases, and so does the natural frequency of theultrasonic blade. A factor to consider is that when the distal end ofthe ultrasonic blade is hot but the waveguide is cold, there is adifferent frequency difference (delta) to achieve a predeterminedtemperature than when the distal end of the ultrasonic blade and thewaveguide are both hot.

In one aspect, the CTM algorithm calculates a change in frequency of theultrasonic transducer drive signal that is required to reach a certainpredetermined temperature as a function of the resonant frequency of theultrasonic electromechanical system at the beginning of activation (atlock). The ultrasonic electromechanical system comprising an ultrasonictransducer coupled to an ultrasonic blade by an ultrasonic waveguide hasa predefined resonant frequency that varies with temperature. Theresonant frequency of the ultrasonic electromechanical system at lockcan be employed to estimate the change in ultrasonic transducer drivefrequency that is required to achieve a temperature end point to accountfor the initial thermal state of the ultrasonic blade. The resonantfrequency of the ultrasonic electromechanical system can vary as afunction of temperature of the ultrasonic transducer or ultrasonicwaveguide or ultrasonic blade or a combination of these components.

FIG. 98 is a graphical representation 133300 of the relationship betweeninitial resonant frequency (frequency at lock) and the change infrequency (delta frequency) required to achieve a temperature ofapproximately 340° C., in accordance with at least one aspect of thepresent disclosure. The change in frequency required to reach anultrasonic blade temperature of approximately 340° C. is shown along thevertical axis and the resonant frequency of the electromechanicalultrasonic system at lock is shown along the horizontal axis. Based onmeasurement data points 133302 shown as scatter plot there is a linearrelationship 133304 between the change in frequency required to reach anultrasonic blade temperature of approximately 340° C. and the resonantfrequency at lock.

At resonant frequency lock, the CTM algorithm employs the linearrelationship 133304 between the lock frequency and the delta frequencyrequired to achieve a temperature just below the melting point of aTEFLON pad (approximately 340° C.). Once the frequency is within acertain buffer distance from a lower bound on frequency, as shown inFIG. 99 , a feedback control system 133310 comprising an ultrasonicgenerator 133312 regulates the electrical current (i) set point appliedto the ultrasonic transducer of the ultrasonic electromechanical system133314 to prevent the frequency (f) of the ultrasonic transducer fromdecreasing lower than a predetermined threshold, in accordance with atleast one aspect of the present disclosure. Decreasing the electricalcurrent set point decreases the displacement of the ultrasonic blade,which in turn decreases the temperature of the ultrasonic blade andincreases the natural frequency of the ultrasonic blade. Thisrelationship allows a change in the electrical current applied to theultrasonic transducer to regulate the natural frequency of theultrasonic blade and indirectly control the temperature of theultrasonic blade or the ultrasonic electromechanical system 133314. Inone aspect, the generator 133312 may be implemented as the ultrasonicgenerator described with reference to FIGS. 2, 7, 8A-8C, and 9A-9B, forexample. The feedback control system 133310 may be implemented as thePID controller described with reference to FIGS. 16-17 , for example.

FIG. 100 is a flow diagram 133320 of a process or logic configuration ofa controlled thermal management (CTM) algorithm to protect the clamp armpad in an ultrasonic end effector, in accordance with at least oneaspect of the present disclosure. The process or logic configurationillustrated by way of the flow diagram 133320 may be executed by theultrasonic generator 133312 as described herein or by control circuitslocated in the ultrasonic instrument or a combination thereof. Aspreviously discussed, the generator 133312 may be implemented as thegenerator described with reference to FIGS. 2, 7, 8A-8C, and 9A-9B, forexample.

In one aspect, initially the control circuit in the generator 133312activates the ultrasonic instrument by applying an electrical current tothe ultrasonic transducer. The resonant frequency of the ultrasonicelectromechanical system is initially locked at initial conditions wherethe ultrasonic blade temperature is cold or close to room temperature.As the temperature of the ultrasonic blade increases due to frictionalcontact with tissue, for example, the control circuit monitors thechange or delta in the resonant frequency of the ultrasonicelectromechanical system and determines 133324 whether the deltafrequency threshold for a predetermined blade temperature has beenreached. If the delta frequency is below the threshold, the processcontinues along the NO branch and the control circuit continues to seek133325 the new resonant frequency and monitor the delta frequency. Whenthe delta frequency meets or exceeds the delta frequency threshold, theprocess continues along the YES branch and calculates 133326 a new lowerfrequency limit (threshold), which corresponds to the melting point ofthe clamp arm pad. In one non-limiting example, the clamp arm pad ismade of TEFLON and the melting point is approximately 340° C.

Once a new frequency lower limit is calculated 133326, the controlcircuit determines 133328 if the resonant frequency is near the newlycalculated lower frequency limit. For example, in the case of a TEFLONclamp arm pad, the control circuit determines 133328 if the ultrasonicblade temperature is approaching 350° C., for example, based on thecurrent resonant frequency. If the current resonant frequency is abovethe lower frequency limit, the process continues along the NO branch andapplies 133330 a normal level of electrical current to the ultrasonictransducer suitable for tissue transection. Alternatively, if thecurrent resonant frequency is at or below the lower frequency limit, theprocess continues along the YES branch and regulates 133332 the resonantfrequency by modifying the electrical current applied to the ultrasonictransducer. In ne aspect, the control circuit employs a PID controlleras described with reference to FIGS. 16-17 , for example. The controlcircuit regulates 133332 the frequency in a loop to determine 133328when the frequency is near the lower limit until the “seal and cut”surgical procedure is terminated and the ultrasonic transducer isdeactivated. Since the CTM algorithm depicted by the logic flow diagram133320 only has an effect at or near the melting point of the clamp armpad, the CTM algorithm is activated after the tissue is transected.

Burst pressure testing conducted on samples indicates that there is noimpact on the burst pressure of the seal when the CTM process or logicconfiguration depicted by the logic flow diagram 133320 is employed toseal and cut vessels or other tissue. Furthermore, based on testsamples, transection times were affected. Moreover, temperaturemeasurements confirm that the ultrasonic blade temperature is bounded bythe CTM algorithm compared to devices without CTM feedback algorithmcontrol and devices that underwent 10 firings at maximum power for tenseconds against the pad with 5 seconds rest between firings showedsignificantly reduced pad wear whereas no device without CTM algorithmfeedback control lasted more than 2 firings in this abuse test.

FIG. 101 is a graphical representation 133340 of temperature versus timecomparing the desired temperature of an ultrasonic blade with a smartultrasonic blade and a conventional ultrasonic blade, in accordance withat least one aspect of the present disclosure. Temperature (deg. C.) isshown along the vertical axis and Time (sec) is shown along thehorizontal axis. In the plot, the dash-dot line is a temperaturethreshold 133342 that represents the desired temperature of theultrasonic blade. The solid line is a temperature versus time curve133344 of a smart ultrasonic blade under the control of the CTMalgorithm described with reference to FIGS. 99 and 100 . The dotted lineis a temperature versus time curve 133346 of a regular ultrasonic bladethat is not under the control of the CTM algorithm described withreference to FIGS. 99 and 100 . As shown. Once the temperature of thesmart ultrasonic blade under the control of the CTM algorithm exceedsthe desired temperature threshold (˜340° C.), the CTM algorithm takescontrol and regulates the temperature of the smart ultrasonic blade tomatch the threshold as closely as possible until the transectionprocedure is completed and the power to the ultrasonic transducer isdeactivated or cut off.

In another aspect, the present disclosure provides a CTM algorithm for a“seal only” tissue effect by an ultrasonic device, such as ultrasonicshears, for example. Generally speaking, ultrasonic surgical instrumentstypically seal and cut tissue simultaneously. Creating an ultrasonicdevice configured to seal only without cutting has not been difficult toachieve using ultrasonic technology alone due to the uncertainty ofknowing when the seal was completed before initiating the cutting. Inone aspect, the CTM algorithm may be configured to protect the endeffector clamp arm pad by allowing the temperature of the ultrasonicblade to exceed the temperature required for cutting (transecting) thetissue but not to exceed the melting point of the clamp arm pad. Inanother aspect, the CTM seal only algorithm may be tuned to exceed thesealing temperature of tissue (approximately 115° C. to approximately180° C. based on experimentation) but not to exceed the cutting(transecting) temperature of tissue (approximately 180° C. toapproximately 350° C.). In the latter configuration, the CTM seal onlyalgorithm provides a “seal only” tissue effect that has beensuccessfully demonstrated. In a linear fit that calculates the change infrequency with respect to the initial lock frequency, as shown in FIG.98 , for example, changing the intercept of the fit regulates the finalsteady state temperature of the ultrasonic blade. By adjusting theintercept parameter, the ultrasonic blade can be set to never exceedapproximately 180° C. resulting in the tissue sealing but not cutting.In one aspect, increasing the clamp force may improve the sealingprocess without impacting clamp arm pad burn through because thetemperature of the blade is controlled by the CTM seal only algorithm.As previously described, the CTM seal only algorithm may be implementedby the generator and PID controller described with reference to FIGS. 2,7, 8A-8C, 9A-9B, and 16-17 , for example. Accordingly, the flow diagram133320 shown in FIG. 100 may be modified such that the control circuitcalculates 133326 a new lower frequency limit (threshold t correspondwith a “seal only” temperature such as, for example, approximately 180°C., determine 133328 when the frequency is near the lower limit, andregulate 133332 the temperature until the “seal only” surgical procedureis terminated and the ultrasonic transducer is deactivated.

In another aspect, the present disclosure provides a cool thermalmonitoring (CTMo) algorithm configured to detect when atraumaticgrasping is feasible. Acoustic ultrasonic energy results in anultrasonic blade temperature of approximately 230° C. to approximately300° C. to achieve the desired effect of cutting or transecting tissue.Because heat is retained in the metal body of the ultrasonic blade for aperiod of time after deactivation of the ultrasonic transducer, theresidual heat stored in the ultrasonic blade can cause tissue damage ifthe ultrasonic end effector is used to grasp tissue before theultrasonic blade has had an opportunity to cool down.

In one aspect, the CTMo algorithm calculates a change in the naturalfrequency of the ultrasonic electromechanical system from the naturalfrequency at a hot state to a natural frequency at a temperature whereatraumatic grasping is possible without damaging the tissue grasped bythe end effector. Directly or a predetermined period of time afteractivating the ultrasonic transducer, a non-therapeutic signal(approximately 5 mA) is applied to the ultrasonic transducer containinga bandwidth of frequencies, approximately 48,000 Hz to 52,000 Hz, forexample, at which the natural frequency is expected to be found. A FFTalgorithm, or other mathematically efficient algorithm of detecting thenatural frequency of the ultrasonic electromechanical system, of theimpedance of the ultrasonic transducer measured during the stimulationof the ultrasonic transducer with the non-therapeutic signal willindicate the natural frequency of the ultrasonic blade as being thefrequency at which the impedance magnitude is at a minimum. Continuallystimulating the ultrasonic transducer in this manner provides continualfeedback of the natural frequency of the ultrasonic blade within afrequency resolution of the FFT or other algorithm for estimating ormeasuring the natural frequency. When a change in natural frequency isdetected that corresponds to a temperature that is feasible foratraumatic grasping, a tone, or a LED, or an on screen display or otherform of notification, or a combination thereof, is provided to indicatethat the device is capable of atraumatic grasping.

In another aspect, the present disclosure provides a CTM algorithmconfigured to tone for seal and end of cut or transection. Providing“tissue sealed” and “end of cut” notifications is a challenge forconventional ultrasonic devices because temperature measurement cannoteasily be directly mounted to the ultrasonic blade and the clamp arm padis not explicitly detected by the blade using sensors. A CTM algorithmcan indicate temperature state of the ultrasonic blade and can beemployed to indicate the “end of cut” or “tissue sealed′”, or both,states because these are temperature-based events.

In one aspect, a CTM algorithm according to the present disclosuredetects the “end of cut” state and activates a notification. Tissuetypically cuts at approximately 210° C. to approximately 320° C. withhigh probability. A CTM algorithm can activate a tone at 320° C. (orsimilar) to indicate that further activation on the tissue is notproductive as that the tissue is probably cut and the ultrasonic bladeis now running against the clamp arm pad, which is acceptable when theCTM algorithm is active because it controls the temperature of theultrasonic blade. In one aspect, the CTM algorithm is programmed tocontrol or regulate power to the ultrasonic transducer to maintain thetemperature of the ultrasonic blade to approximately 320° C. when thetemperature of the ultrasonic blade is estimated to have reached 320° C.Initiating a tone at this point provides an indication that the tissuehas been cut. The CTM algorithm is based on a variation in frequencywith temperature. After determining an initial state temperature (basedon initial frequency), the CTM algorithm can calculate a frequencychange that corresponds to a temperature that implies when the tissue iscut. For example, if the starting frequency is 51,000 Hz, the CTMalgorithm will calculate the change in frequency required to achieve320° C. which might be −112 Hz. It will then initiate control tomaintain that frequency set point (e.g., 50,888 Hz) thereby regulatingthe temperature of the ultrasonic blade. Similarly, a frequency changecan be calculated based on an initial frequency that indicates when theultrasonic blade is at a temperature which indicates that the tissue isprobably cut. At this point, the CTM algorithm does not have to controlpower, but simply initiate a tone to indicate the state of the tissue orthe CTM algorithm can control frequency at this point to maintain thattemperature if desired. Either way, the “end of cut” is indicated.

In one aspect, a CTM algorithm according to the present disclosuredetects the “tissue sealed” state and activates a notification. Similarto the end of cut detection, tissue seals between approximately 105° C.and approximately 200° C. The change in frequency from an initialfrequency required to indicate that a temperature of the ultrasonicblade has reached 200° C., which indicates a seal only state, can becalculated at the onset of activation of the ultrasonic transducer. TheCTM algorithm can activate a tone at this point and if the surgeonwishes to obtain a seal only state, the surgeon could stop activation orto achieve a seal only state the surgeon could stop activation of theultrasonic transducer and automatically initiate a specific seal onlyalgorithm from this point on or the surgeon could continue activation ofthe ultrasonic transducer to achieve a tissue cut state.

Application of Smart Ultrasonic Blade Technology

When an ultrasonic blade is immersed in a fluid-filled surgical field,the ultrasonic blade cools down during activation rendering lesseffective for sealing and cutting tissue in contact therewith. Thecooling down of the ultrasonic blade may lead to longer activation timesand/or hemostasis issues because adequate heat is not delivered to thetissue. In order to overcome the cooling of the ultrasonic blade, moreenergy delivery may be required to shorten the transection times andachieve suitable hemostasis under these fluid immersion conditions.Using a frequency-temperature feedback control system, if the ultrasonicblade temperature is detected to, either start out below, or remainbelow a certain temperature for a certain period of time, the outputpower of the generator can be increased to compensate for cooling due toblood/saline/other fluid present in the surgical field.

Accordingly, the frequency-temperature feedback control system describedherein can improve the performance of an ultrasonic device especiallywhen the ultrasonic blade is located or immersed, partially or wholly,in a fluid-filled surgical field. The frequency-temperature feedbackcontrol system described herein minimizes long activation times and/orpotential issues with ultrasonic device performance in fluid-filledsurgical field.

As previously described, the temperature of the ultrasonic blade may beinferred by detecting the impedance of the ultrasonic transducer givenby the following expression:

${Z_{g}(t)} = \frac{V_{g}(t)}{I_{g}(t)}$

or equivalently, detecting the phase angle φ between voltage V_(g)(t)current I_(g)(t) signals applied to the ultrasonic transducer. The phaseangle φ information also may be used to infer the conditions of theultrasonic blade. As discussed with particularity herein, the phaseangle φ changes as a function of the temperature of the ultrasonicblade. Therefore, the phase angle φ information may be employed tocontrol the temperature of the ultrasonic blade. This may be done, forexample, by reducing the power delivered to the ultrasonic blade whenthe ultrasonic blade runs too hot and increasing the power delivered tothe ultrasonic blade when the ultrasonic blade runs too cold. FIGS.102A-102B are graphical representations of temperature feedback controlfor adjusting ultrasonic power applied to an ultrasonic transducer whena sudden drop in temperature of an ultrasonic blade is detected.

FIG. 102A is a graphical representation of ultrasonic power output133070 as a function of time, in accordance with at least one aspect ofthe present disclosure. Power output of the ultrasonic generator isshown along the vertical axis and time (sec) is shown along thehorizontal axis. FIG. 102B is a graphical representation of ultrasonicblade temperature 133080 as a function of time, in accordance with atleast one aspect of the present disclosure. Ultrasonic blade temperatureis shown along the vertical axis and time (sec) is shown along thehorizontal axis. The temperature of the ultrasonic blade increases withthe application of constant power 133072 as shown in FIG. 102A. Duringuse, the temperature of the ultrasonic blade suddenly drops. This mayresult from a variety of conditions, however, during use, it may beinferred that the temperature of the ultrasonic blade drops when it isimmersed in a fluid-filled surgical field (e.g., blood, saline, water,etc.). At time to, the temperature of the ultrasonic blade drops belowthe desired minimum temperature 133082 and the frequency-temperaturefeedback control algorithm detects the drop in temperature and begins toincrease or “ramp up” the power as shown by the power ramp 133074delivered to the ultrasonic blade to start raising the temperature ofthe ultrasonic blade above the desired minimum temperature 133082.

With reference to FIGS. 102A and 102B, the ultrasonic generator isoutputs substantially constant power 133072 as long the temperature ofthe ultrasonic blade remains above the desired minimum temperature133082. At to, processor or control circuit in the generator orinstrument or both detects the drop in temperature of the ultrasonicblade below the desired minimum temperature 133072 and initiates afrequency-temperature feedback control algorithm to raise thetemperature of the ultrasonic blade above the minimum desiredtemperature 133082. Accordingly, the generator power begins to ramp133074 at ti corresponding to the detection of a sudden drop in thetemperature of the ultrasonic blade at to. Under thefrequency-temperature feedback control algorithm, the power continues toramp 133074 until the temperature of the ultrasonic blade is above thedesired minimum temperature 133082.

FIG. 103 is a logic flow diagram 133090 of a process depicting a controlprogram or a logic configuration to control the temperature of anultrasonic blade, in accordance with at least one aspect of the presentdisclosure. According to the process, the processor or control circuitof the generator or instrument or both executes one aspect of afrequency-temperature feedback control algorithm discussed in connectionwith FIGS. 102A and 102B to apply 133092 a power level to the ultrasonictransducer to achieve a desired temperature at the ultrasonic blade. Thegenerator monitors 133094 the phase angle φ between the voltage V_(g)(t)and current I_(g)(t) signals applied to drive the ultrasonic transducer.Based on the phase angle φ, the generator infers 133096 the temperatureof the ultrasonic blade using the techniques described herein inconnection with FIGS. 94A-96 . The generator determines 133098 whetherthe temperature of the ultrasonic blade is below a desired minimumtemperature by comparing the inferred temperature of the ultrasonicblade to a predetermined desired temperature. The generator then adjuststhe power level applied to the ultrasonic transducer based on thecomparison. For example, the process continues along NO branch when thetemperature of the ultrasonic blade is at or above the desired minimumtemperature and continues along YES branch when the temperature of theultrasonic blade is below the desired minimum temperature. When thetemperature of the ultrasonic blade is below the desired minimumtemperature, the generator increases 133100 the power level to theultrasonic transducer, e.g., by increasing the voltage V_(g)(t) and/orcurrent I_(g)(t) signals, to raise the temperature of the ultrasonicblade and continues increasing the power level applied to the ultrasonictransducer until the temperature of the ultrasonic blade increases abovethe minimum desired temperature.

Adaptive Advanced Tissue Treatment Pad Saver Mode

FIG. 104 is a graphical representation 133110 of ultrasonic bladetemperature as a function of time during a vessel firing, in accordancewith at least one aspect of the present disclosure. A plot 133112 ofultrasonic blade temperature is graphed along the vertical axis as afunction of time along the horizontal axis. The frequency-temperaturefeedback control algorithm combines the temperature of the ultrasonicblade feedback control with the jaw sensing ability. Thefrequency-temperature feedback control algorithm provides optimalhemostasis balanced with device durability and can deliver energyintelligently for best sealing while protecting the clamp arm pad.

As shown in FIG. 104 , the optimum temperature 133114 for vessel sealingis marked as a first target temperature T₁ and the optimum temperature133116 for “infinite” clamp arm pad life is marked as a second targettemperature T₂. The frequency-temperature feedback control algorithminfers the temperature of the ultrasonic blade and maintains thetemperature of the ultrasonic blade between the first and second targettemperature thresholds T₁ and T₂. The generator power output is thusdriven to achieve optimal ultrasonic blade temperatures for sealingvessels and prolonging the life of the clamp arm pad.

Initially, the temperature of the ultrasonic blade increases as theblade heats up and eventually exceeds the first target temperaturethreshold T₁. The frequency-temperature feedback control algorithm takesover to control the temperature of the blade to T₁ until the vesseltransection is completed 133118 at to and the ultrasonic bladetemperature drops below the second target temperature threshold T₂. Aprocessor or control circuit of the generator or instrument or bothdetects when the ultrasonic blade contacts the clamp arm pad. Once thevessel transection is completed at to and detected, thefrequency-temperature feedback control algorithm switches to controllingthe temperature of the ultrasonic blade to the second target thresholdT₂ to prolong the life of the clam arm pad. The optimal clamp arm padlife temperature for a TEFLON clamp arm pad is approximately 325° C. Inone aspect, the advanced tissue treatment can be announced to the userat a second activation tone.

FIG. 105 is a logic flow diagram 133120 of a process depicting a controlprogram or a logic configuration to control the temperature of anultrasonic blade between two temperature set points as depicted in FIG.104 , in accordance with at least one aspect of the present disclosure.According to the process, the generator executes one aspect of thefrequency-temperature feedback control algorithm to apply 133122 a firstpower level to the ultrasonic transducer, e.g., by adjusting the voltageV_(g)(t) and/or the current I_(g)(t) signals applied to the ultrasonictransducer, to set the ultrasonic blade temperature to a first target T₁optimized for vessel sealing. As previously described, the generatormonitors 133124 the phase angle φ between the voltage V_(g)(t) andcurrent I_(g)(t) signals applied to the ultrasonic transducer and basedon the phase angle φ, the generator infers 133126 the temperature of theultrasonic blade using the techniques described herein in connectionwith FIGS. 94A-96 . According to the frequency-temperature feedbackcontrol algorithm, a processor or control circuit of the generator orinstrument or both maintains the ultrasonic blade temperature at thefirst target temperature T₁ until the transection is completed. Thefrequency-temperature feedback control algorithm may be employed todetect the completion of the vessel transection process. The processoror control circuit of the generator or instrument or both determines133128 when the vessel transection is complete. The process continuesalong NO branch when the vessel transection is not complete andcontinues along YES branch when the vessel transection is complete.

When the vessel transection in not complete, the processor or controlcircuit of the generator or instrument or both determines 133130 if thetemperature of the ultrasonic blade is set at temperature T₁ optimizedfor vessel sealing and transecting. If the ultrasonic blade temperatureis set at T₁, the process continues along the YES branch and theprocessor or control circuit of the generator or instrument or bothcontinues to monitor 133124 the phase angle φ between the voltageV_(g)(t) and current I_(g)(t) signals applied to the ultrasonictransducer and based on the phase angle φ. If the ultrasonic bladetemperature is not set at T₁, the process continues along NO branch andthe processor or control circuit of the generator or instrument or bothcontinues to apply 133122 a first power level to the ultrasonictransducer.

When the vessel transection is complete, the processor or controlcircuit of the generator or instrument or both applies 133132 a secondpower level to the ultrasonic transducer to set the ultrasonic blade toa second target temperature T₂ optimized for preserving or extending thelife of the clamp arm pad. The processor or control circuit of thegenerator or instrument or both determines 133134 if the temperature ofthe ultrasonic blade is at set temperature T₂. If the temperature of theultrasonic blade is set at T2, the process completes 133136 the vesseltransection procedure.

Start Temperature of Blade

Knowing the temperature of the ultrasonic blade at the beginning of atransection can enable the generator to deliver the proper quantity ofpower to heat up the blade for a quick cut or if the blade is alreadyhot add only as much power as would be needed. This technique canachieve more consistent transection times and extend the life of theclam arm pad (e.g., a TEFLON clamp arm pad). Knowing the temperature ofthe ultrasonic blade at the beginning of the transection can enable thegenerator to deliver the right amount of power to the ultrasonictransducer to generate a desired amount of displacement of theultrasonic blade.

FIG. 106 is a logic flow diagram 133140 of a process depicting a controlprogram or a logic configuration to determine the initial temperature ofan ultrasonic blade, in accordance with at least one aspect of thepresent disclosure. To determine the initial temperature of anultrasonic blade, at the manufacturing plant, the resonant frequenciesof ultrasonic blades are measured at room temperature or at apredetermined ambient temperature. The baseline frequency values arerecorded and stored in a lookup table of the generator or instrument orboth. The baseline values are used to generate a transfer function. Atthe start of an ultrasonic transducer activation cycle, the generatormeasures 133142 the resonant frequency of the ultrasonic blade andcompares 133144 the measured resonant frequency to the baseline resonantfrequency value and determines the difference in frequency (Δf). The Δfis compared to the lookup table or transfer function for correctedultrasonic blade temperature. The resonant frequency of the ultrasonicblade may be determined by sweeping the frequency of the voltageV_(g)(t) and current I_(g)(t) signals applied to the ultrasonictransducer. The resonant frequency is that frequency at which the phaseangle φ voltage V_(g)(t) and current I_(g)(t) signals is zero asdescribed herein.

Once the resonant frequency of the ultrasonic blade is determined, theprocessor or control circuit of the generator or instrument or bothdetermines 133146 the initial temperature of the ultrasonic blade basedon the difference between the measured resonant frequency and thebaseline resonant frequency. The generator sets the power leveldelivered the ultrasonic transducer, e.g., by adjusting the voltageV_(g)(t) or current I_(g)(t) drive signals or both, to one of thefollowing values prior to activating the ultrasonic transducer.

The processor or control circuit of the generator or instrument or bothdetermines 133148 if the initial temperature of the ultrasonic blade islow. If the initial temperature of the ultrasonic blade is low, theprocess continues along YES branch and the processor or control circuitof the generator or instrument or both applies 133152 a high power levelto the ultrasonic transducer to increase the temperature of theultrasonic blade and completes 133156 the vessel transection procedure.

If the initial temperature of the ultrasonic blade is not low, theprocess continues along NO branch and the processor or control circuitof the generator or instrument or both determines 133150 if the initialtemperature of the ultrasonic blade is high. If the initial temperatureof the ultrasonic blade is high, the process proceeds along YES branchand the processor or control circuit of the generator or instrument orboth applies 133154 a low power level to the ultrasonic transducer todecrease the temperature of the ultrasonic blade and completes 133156the vessel transection procedure. If the initial temperature of theultrasonic blade is not high, the process continues along NO branch andthe processor or control circuit of the generator or instrument or bothcompletes 133156 the vessel transection.

Smart Blade Technology to Control Blade Instability

The temperature of an ultrasonic blade and the contents within the jawsof an ultrasonic end effector can be determined using thefrequency-temperature feedback control algorithms described herein. Thefrequency/temperature relationship of the ultrasonic blade is employedto control ultrasonic blade instability with temperature.

As described herein, there is a well-known relationship between thefrequency and temperature in ultrasonic blades. Some ultrasonic bladesexhibit displacement instability or modal instability in the presence ofincreasing temperature. This known relationship may be employed tointerpret when an ultrasonic blade is approaching instability and thenadjusting the power level driving the ultrasonic transducer (e.g., byadjusting the driving voltage V_(g)(t) or current I_(g)(t) signals, orboth, applied to the ultrasonic transducer) to modulate the temperatureof the ultrasonic blade to prevent instability of the ultrasonic blade.

FIG. 107 is a logic flow diagram 133160 of a process depicting a controlprogram or a logic configuration to determine when an ultrasonic bladeis approaching instability and then adjusting the power to theultrasonic transducer to prevent instability of the ultrasonictransducer, in accordance with at least one aspect of the presentdisclosure. The frequency/temperature relationship of an ultrasonicblade that exhibits a displacement or modal instability is mapped bysweeping the frequency of the drive voltage V_(g)(t) or current I_(g)(t)signals, or both, over the temperature of the ultrasonic blade andrecording the results. A function or relationship is developed that canbe used/interpreted by a control algorithm executed by the generator.Trigger points can be established using the relationship to notify thegenerator that an ultrasonic blade is approaching the known bladeinstability. The generator executes a frequency-temperature feedbackcontrol algorithm processing function and closed loop response such thatthe driving power level is reduced (e.g., by lowering the drivingvoltage V_(g)(t) or current I_(g)(t), or both, applied to the ultrasonictransducer) to modulate the temperature of the ultrasonic blade at orbelow the trigger point to prevent a given blade from reachinginstability.

Advantages include simplification of ultrasonic blade configurationssuch that the instability characteristics of the ultrasonic blade do notneed to be designed out and can be compensated using the presentinstability control technique. The present instability control techniquealso enables new ultrasonic blade geometries and can improve stressprofile in heated ultrasonic blades. Additionally, ultrasonic blades canbe configured to diminish performance of the ultrasonic blade if usedwith generators that do not employ this technique.

In accordance with the process depicted by the logic flow diagram133160, the processor or control circuit of the generator or instrumentor both monitors 133162 the phase angle φ between the voltage V_(g)(t)and current I_(g)(t) signals applied to the ultrasonic transducer. Theprocessor or control circuit of the generator or instrument or bothinfers 133164 the temperature of the ultrasonic blade based on the phaseangle φ between the voltage V_(g)(t) and current I_(g)(t) signalsapplied to the ultrasonic transducer. The processor or control circuitof the generator or instrument or both compares 133166 the inferredtemperature of the ultrasonic blade to an ultrasonic blade instabilitytrigger point threshold. The processor or control circuit of thegenerator or instrument or both determines 133168 whether the ultrasonicblade is approaching instability. If not, the process proceed along theNO branch and monitors 133162 the phase angle φ, infers 133164 thetemperature of the ultrasonic blade, and compares 133166 the inferredtemperature of the ultrasonic blade to an ultrasonic blade instabilitytrigger point threshold until the ultrasonic blade approachesinstability. The process then proceeds along the YES branch and theprocessor or control circuit of the generator or instrument or bothadjusts 133170 the power level applied to the ultrasonic transducer tomodulate the temperature of the ultrasonic blade.

Ultrasonic Sealing Algorithm With Temperature Control

Ultrasonic sealing algorithms for ultrasonic blade temperature controlcan be employed to improve hemostasis utilizing a frequency-temperaturefeedback control algorithm described herein to exploit thefrequency/temperature relationship of ultrasonic blades.

In one aspect, a frequency-temperature feedback control algorithm may beemployed to alter the power level applied to the ultrasonic transducerbased on measured resonant frequency (using spectroscopy) which relatesto temperature, as described in various aspects of the presentdisclosure. In one aspect, the frequency-temperature feedback controlalgorithm may be activated by an energy button on the ultrasonicinstrument.

It is known that optimal tissue effects may be obtained by increasingthe power level driving the ultrasonic transducer (e.g., by increasingthe driving voltage V_(g)(t) or current I_(g)(t), or both, applied tothe ultrasonic transducer) early on in the sealing cycle to rapidly heatand desiccate the tissue, then lowering the power level driving theultrasonic transducer (e.g., by lowering the driving voltage V_(g)(t) orcurrent I_(g)(t), or both, applied to the ultrasonic transducer) toslowly allow the final seal to form. In one aspect, afrequency-temperature feedback control algorithm according to thepresent disclosure sets a limit on the temperature threshold that thetissue can reach as the tissue heats up during the higher power levelstage and then reduces the power level to control the temperature of theultrasonic blade based on the melting point of the clamp jaw pad (e.g.,TEFLON) to complete the seal. The control algorithm can be implementedby activating an energy button on the instrument for a moreresponsive/adaptive sealing to reduce more the complexity of thehemostasis algorithm.

FIG. 108 is a logic flow diagram 133180 of a process depicting a controlprogram or a logic configuration to provide ultrasonic sealing withtemperature control, in accordance with at least one aspect of thepresent disclosure. According to the control algorithm, the processor orcontrol circuit of the generator or instrument or both activates 133182ultrasonic blade sensing using spectroscopy (e.g., smart blade) andmeasures 133184 the resonant frequency of the ultrasonic blade (e.g.,the resonant frequency of the ultrasonic electromechanical system) todetermine the temperature of the ultrasonic blade using afrequency-temperature feedback control algorithm (spectroscopy) asdescribed herein. As previously described, the resonant frequency of theultrasonic electromechanical system is mapped to obtain the temperatureof the ultrasonic blade as a function of resonant frequency of theelectromechanical ultrasonic system.

A first desired resonant frequency f of the ultrasonic electromechanicalsystem corresponds to a first desired temperature Z° of the ultrasonicblade. In one aspect, the first desired ultrasonic blade temperature Z°is an optimal temperature (e.g., 450° C.) for tissue coagulation. Asecond desired frequency f_(r) of the ultrasonic electromechanicalsystem corresponds to a second desired temperature ZZ° of the ultrasonicblade. In one aspect, the second desired ultrasonic blade temperatureZZ° is a temperature of 330° C., which is below the melting point of theclamp arm pad, which is approximately 380° C. for TEFLON.

The processor or control circuit of the generator or instrument or bothcompares 133186 the measured resonant frequency of the ultrasonicelectromechanical system to the first desired frequency f. In otherwords, the process determines whether the temperature of the ultrasonicblade is less than the temperature for optimal tissue coagulation. Ifthe measured resonant frequency of the ultrasonic electromechanicalsystem is less than the first desired frequency f_(x), the processcontinues along the NO branch and the processor or control circuit ofthe generator or instrument or both increases 133188 the power levelapplied to the ultrasonic transducer to increase the temperature of theultrasonic blade until the measured resonant frequency of the ultrasonicelectromechanical system exceeds the first desired frequency f_(x). Inwhich case, the tissue coagulation process is completed and the processcontrols the temperature of the ultrasonic blade to the second desiredtemperature corresponding to the second desired frequency f_(y).

The process continues along the YES branch and the processor or controlcircuit of the generator or instrument or both decreases 133190 thepower level applied to the ultrasonic transducer to decrease thetemperature of the ultrasonic blade. The processor or control circuit ofthe generator or instrument or both measures 133192 the resonantfrequency of the ultrasonic electromechanical system and compares themeasured resonant frequency to the second desired frequency f_(Y). Ifthe measured resonant frequency is not less than the second desiredfrequency f_(Y), the processor or control circuit of the generator orinstrument or both decreases 133190 the ultrasonic power level until themeasured resonant frequency is less than the second desired frequencyf_(Y). The frequency-temperature feedback control algorithm to maintainthe measured resonant frequency of the ultrasonic electromechanicalsystem below the second desired frequency f_(y), e.g., the temperatureof the ultrasonic blade is less than the temperature of the meltingpoint of the clamp arm pad then, the generator executes the increasesthe power level applied to the ultrasonic transducer to increase thetemperature of the ultrasonic blade until the tissue transection processis complete 133196.

FIG. 109 is a graphical representation 133200 of ultrasonic transducercurrent and ultrasonic blade temperature as a function of time, inaccordance with at least one aspect of the present disclosure. FIG. 109illustrates the results of the application of the frequency-temperaturefeedback control algorithm described in FIG. 109 . The graphicalrepresentation 133200 depicts a first plot 133202 of ultrasonic bladetemperature as a function of time with respect to a second plot 133204of ultrasonic transducer current I_(g)(t) as a function of time. Asshown, the transducer I_(g)(t) is maintained constant until theultrasonic blade temperature reaches 450°, which is an optimalcoagulation temperature. Once the ultrasonic blade temperature reaches450°, the frequency-temperature feedback control algorithm decrease thetransducer current I_(g)(t) until the temperature of the ultrasonicblade drops to below 330°, which is below the melting point of a TEFLONpad, for example.

Limiting Capacitive Coupling and its Effects

Aspects of the present disclosure are presented for a surgicalinstrument with improved device capabilities for reducing undesiredoperational side effects. In particular, the surgical instrument mayinclude means for limiting capacitive coupling to improve monopolarisolation for use independently or in cooperation with another advancedenergy modality. Capacitive coupling occurs generally when there is atransfer of energy between nodes, induced by an electric field. Duringsurgery, capacitive coupling may occur when two or more electricalsurgical instruments are being used in or around a patient. While insome cases capacitive coupling may be desirable, as additional devicesmay be powered inductively by capacitive coupling, having capacitivecoupling occur accidentally during surgery or around a patient generallycan have extremely deleterious consequences. Parasitic or accidentalcapacitive coupling may occur in unknown or unpredictable locations,causing energy to be applied to unintended areas. When the patient isunder anesthesia and unable to provide any response, parasiticcapacitive coupling can burn a patient while the surgeon would not knowit is even occurring. It is therefore desirable to limit the parasiticor accidental capacitive coupling in surgical instruments and duringsurgery generally.

In some aspects, a system including a surgical instrument and agenerator may be configured to interrupt the transmission of energy fromthe generator to the surgical instrument when capacitive coupling hasbeen detected. One or more safety fuses, sensors, controls, and/oralgorithms may be in place to automatically trigger an interruption ofthe generator in these scenarios. Alerts, including audio signals,vibrations, and visual messages may issue to inform the surgery teamthat the generator was interrupted due to the detection of capacitivecoupling.

In some aspects, the system includes means for detecting that acapacitive coupling event has occurred. For example, an algorithm thatincludes inputs from one or more sensors for monitoring events aroundthe system may apply situational awareness and other programmatic meansto conclude that capacitive coupling is occurring somewhere within thesystem and react accordingly. A system having situational awarenessmeans that the system may be configured to anticipate scenarios that mayarise based on present environmental and system data and determiningthat the present conditions follow a pattern that gives rise topredictable next steps. As an example, the system may apply situationalawareness in the context of handling capacitive coupling events byrecalling instances in similarly situated surgeries where various sensordata is detected. The sensor data may indicate an increase in current attwo particular locations along a closed loop electrosurgical system,that based on previous data of similarly situated surgeries, indicates ahigh likelihood that a capacitive coupling event is imminent.

In some aspects, the surgical instruments may be modified in structureto limit the occurrence of capacitive coupling, or in other cases reducethe collateral damage caused by capacitive coupling. For example,additional insulation placed strategically in or around the surgicalinstrument may help limit the incidence of capacitive coupling. In othercases, the end effector of the surgical instrument may include modifiedstructures that reduce the incidence of current displacement, such asrounding the tips of the end effector or specifically shaping the bladeof the end effector to behave more like a monopolar blade while stillacting as a bipolar device.

In some aspects, the system may include passive means for mitigating orlimiting the effects of the capacitive coupling. For example, the systemmay include leads that can shunt the energy to a neutral node throughconductive passive components. In general, any and all of these aspectsmay be combined or included in a single system to address the challengesposed by multiple electrical components liable to cause capacitivecoupling during patient surgery.

FIG. 110 provides a diagram showing an example system 134000 with meansfor detecting capacitive coupling, in accordance with at least oneaspect of the present disclosure. The system 134000 includes a monopolarESU generator 134002 that is electrically coupled to a surgicalinstrument 134008. The surgical instrument 134008 is used to performsurgery on a patient, where patient tissue 134016 is shown to representthe surgical site of the patient where surgery is being performed. Thesurgical instrument 134008 may include means for applyingelectrosurgical or ultrasonic energy to an end effector, and in somecases may include a blade and/or a pair of jaws to grasp or clamp ontotissue. The energy powered by the ESU generator 134002 may touch thepatient through the end effector, via any of the possible variouscomponents of the end effector. At least a portion of the patient mayrest on a return path pad 134014, such as a Smart Megasoft Pad™, forexample, that is configured to divert excess energy away from thepatient when the surgical instrument 134008 touches the patient andapplies electrosurgical energy.

Because of the multiple electrical sources near the patient, parasiticcapacitive coupling is ever present and always a danger to harm thepatient during surgery. Because the patient is not expected to expressany reaction during surgery, if unknown or unpredicted capacitivecoupling occurs, the patient may experience burns in unintended placesas a result. In general, energy anomalies like capacitive couplingshould be minimized or otherwise corrected in order to improve patientsafety. To limit the occurrence of capacitive coupling or other types ofenergy anomalies, multiple smart sensors or monitors, such as CT1(134006), CT2 (134010), and CT3 (134012) smart sensors may be integratedinto the electrosurgical system as indicators to determine whetherexcess or inductive energy is radiating outside the one or more of theelectrical sources. As shown in FIG. 110 , the smart sensors CT1(134006), CT2 (134010) and CT3 (134012) are placed at likely locationswhere energy may inductively radiate. The sensors or monitors may beconfigured to detect capacitance, and if placed at strategic locationswithin the system, a reading of capacitance may imply that capacitiveleakage is occurring near the sensor or monitor. Coupled with knowledgeof other sensors nearby or throughout the system not indicating areading of capacitance, one may conclude that capacitive leakage isoccurring in close proximity to the sensor or monitor that is providinga positive indication. Other sensors may be used, such as capacitiveleakage monitors or detectors. These sensors may be configured toprovide an alert, such as lighting up or delivering a noise ortransmitting a signal ultimately to a display monitor. In addition, themonopolar ESU 134002 may be configured to automatically trigger aninterruption in energy generation to stop any further capacitivecoupling from occurring.

In some aspects, a neutral electrode 134004 may be included in themonopolar ESU 134002 and may be electrically coupled to the return pathpad 134014, such as a Smart Megasoft Pad®, for example, as anothersolution to reduce capacitive coupling. Energy can reach the neutralnode 134004 conductively as the electrosurgical instrument 134008touches the patient, the patient is touching the return path pad 134014,and the pad is conductively connected to the neutral electrode 134004.Thus, energy can be diverted to the neutral node 134004 from themonopolar ESU 134002 or the surgical instrument 134008 and therebyreduce the incidence of capacitive coupling.

In some aspects, a cloud analytics system communicatively coupled to themonopolar ESU, such as through a medical hub, may be configured toemploy situational awareness that can help anticipate when capacitivecoupling may occur during surgery. The cloud analytics system and/or themedical hub may utilize a capacitive coupling algorithm to monitor theincidence of energy flowing through the surgical system, and based onprevious data about the state of energy in the system for a similarsituated procedure, may conclude there is a likelihood that capacitivecoupling may occur if no additional action is taken. For example, duringa surgery involving prescribed methods for how to the surgicalinstrument and how much power should be employed during particular stepsin the surgery, the cloud analytics module may draw from previoussurgeries of the same and note that capacitive coupling has a strongerlikelihood to occur after a particular step in the surgery. Whilemonitoring the steps in the surgery, when the same or very similarenergy profiles occur during or just before the expected step that tendsto induce capacitive coupling, the cloud analytics system may deliver analert that indicates this is likely to cause capacitive coupling. Thesurgeon may be given the option to reduce peak voltage in the surgicalinstrument 134008 or interrupt the power generation by the monopolar ESU134002, or the cloud analytics module may automatically cause themedical hub to take these measures. This may lead to eliminating thepossibility of capacitive coupling before it has a chance to occur, orat least may limit any unintended effects caused by a momentaryoccurrence of capacitive coupling.

In some aspects, the surgical instrument as shown in FIG. 110 mayinclude structural means for reducing or preventing capacitive coupling.For example, insulation in the shaft of the surgical instrument 134008may reduce the incidence of inductance. In other cases, the monopolarwire connecting the monopolar ESU 134002 to the surgical instrument134008 may be shielded. As another example, interrupting plasticelements within the shaft may be intermittently present to preventcapacitive coupling from transmitting long distance within the shaft.Other insulator-type elements may be used to achieve similar effects. Insome aspects, the monopolar wire electrically connecting the surgicalinstrument 134008 to the generator 134002 may be shielded to also reducethe incidence of capacitive coupling.

In some aspects, the structure of the end effector may be modified toreduce the effects of capacitive coupling as the end effector makescontact with the patient. As one example, the jaws of the end effectormay be designed to have only one side of the each of the jaws directedto deliver energy, thereby causing the end effector to act like amonopolar blade while still actually functionally structured as abipolar device. In one example of this, the ends or tips of the endeffector may be shaped like a duck bill, with rounded ends to reduce anyvoltage peaks that might arise out of pointed ends. The direction ofenergy in the end effector may still be directed to an area or a pointalong the duck billed ends, but the dispersion of any excess energy maybe blunted by the duck billed end. As another example, the blade may bestructured to be slightly thicker on one side, such as having atriangular cross-sectional area, and having a thin standing upper bladeelement on the opposite. This may allow any energy being delivered tothe blade to be focused to a point, which may help the surgicalinstrument act like a monopolar blade while still being a bipolardevice. In this way, energy will not be dispersed that would make thesurgical instrument more prone to causing capacitive coupling. As afinal example, the jaws of the surgical instrument may have electrodesplaced on the inside of the end effector, allowing the outer portions ofthe end effector to act like a shield to ward against capacitivecoupling. The electrodes may still be placed sufficiently to contact thetissue of the patient during a surgery, while having one or more edgesof the end effector shield the energy from dispersing beyond the focusedsurgical area.

FIG. 111 is a logic flow diagram 134100 depicting a control program or alogic configuration of an example methodology for limiting the effectsof capacitive coupling in a surgical system is disclosed, according tosome aspects. The example methodology may be consistent with thedescriptions above regarding several enumerated means for limitingcapacitive coupling or mitigating its effects during surgery using oneor more surgical instruments.

As shown and consistent with the examples discussed above, themethodology 134100 may start with the surgical system being configuredto monitor 134102 energy generation. For example, multiple sensors maybe placed strategically at potential vulnerable points more liable toleak energy that can cause capacitive coupling. These sensors may beconfigured to deliver an alert when an energy anomaly occurs.

Continuing on, the sensors or other detecting means may detect 134104 avoltage anomaly, such as a voltage peak or voltage spike, at one or morelocations along the surgical system that would not normally be expectedto produce such energy production. The system may be configured toconclude these scenarios may give rise to parasitic capacitive coupling,potentially burning the patient unbeknownst to the surgery team in theabsence of any alerts. As a result, an alert or message may be deliveredindicating the energy anomaly and the danger of capacitive couplingoccurring.

In some aspects, situational awareness also may be used to anticipate134106 when capacitive coupling is more likely to occur during the usualcourse of a surgery. Situational awareness may be used to refer back topast surgical operations of similar type or circumstances to identifywhat variables may be present when capacitive coupling was determined tohave occurred. If there are certain steps in the procedure that are morelikely to cause capacitive coupling, the system may anticipate thesesituations by particularly monitoring the sensors at these times, and/ortaking preemptive measures to reduce the incidences of capacitivecoupling.

If capacitive coupling is detected or believed to be imminent, based onthe above the methodology 134100 executed by the surgical system,measures taken to reduce, eliminate, or mitigate the effects ofcapacitive coupling can include to automatically interrupt 134108 energygeneration at the monopolar energy generator, according to some aspects.It is noted that some loss in surgical operation may occur momentarilyat the time this interruption is enabled, but preventing unintendeddamage to the patient would be paramount in any case. The surgery cancontinue as planned after a brief moment of interruption.

Measuring the energy out relative to energy in, taking advantage ofparasitic leakage to improve pad contact, or turn power off, generatorknows how much current it's generating, and you're measuring the energythat is put out.

Increasing Frequency in the Presence of Capacitive Coupling

In some aspects, the presence of parasitic capacitive coupling can beharnessed to perform energy coagulation or energy cautery. In certaininstances, it may be desirable to increase the energy generation of theelectrosurgical instrument in order to drive the monopolar circuit toground, through the body of the patient. While there may be a number ofinstances where the monopolar circuit is completed through theconductivity drawn by a conductive return pad 134014, such as the SmartMegasoft Pad® (see FIG. 110 ), in some cases the pad may be defective orworn, such that the conductivity of the return pad 134014 is notsufficient to draw the current of the electrosurgical instrument (e.g.,134008) through the body of the patient. In such cases, the current maylack a sufficient ground for the energy to travel to, effectively makingthe body of the patient act like a short circuit. This may render theelectrosurgery ineffective, as the energy delivered by the surgicalinstrument 134008 will not pass through the tissue of the patient andtherefore not heat the tissue as intended. A similar situation may occurwhen there is no return pad at all. That is, without a conductive returnpad 134014, such as the Smart Megasoft Pad®, to provide a wideconductive return path, there may be no ground available that isconnected to the patient. This also may lead to the patient acting as ashort circuit if energy from the surgical instrument were applied to thepatient.

To adjust for these situations, in some aspects, the monopolar energygeneration may be increased to a very high frequency, such as 500 Khz to3-4 Mhz, to take advantage of parasitic patient leakage to do padlesselectrosurgery (or electrosurgery with insufficient conductivity in thepad). By increasing the alternating current frequency, the parasiticleakage current will increase. The stronger leakage current can thenmore effectively radiatively traverse through the body of the patient.After reaching through the body of the patient, the leakage current ofthe capacitive coupling may be more effectively radiatively coupled to aground state as a result, which may effectively drive the currentradiatively into another object that acts as ground. For example, if theAC frequency is high enough, the current leakage may reach the monopolargenerator grounding terminal. This will help to remove the short circuiteffect of the patient, thereby allowing for the energy coagulation totake place. Therefore, in the situations where there is a non-paddedsystem, or a system with poor conductivity in a pad, it may be desirableto increase current leakage in order to take advantage of higher leakagereturn that can be used to complete the monopolar circuit. That is, insome cases, the return path may be formed by the radiative currentleakage caused by capacitive coupling. To help ensure that the radiativereturn path reaches a ground plane, the energy of the surgicalinstrument may be increased to a very high frequency.

In some cases, the poorly conducting return pad may be connectedpurposely to an earth ground, or table, or to a closest support surface,while the return connector on the generator may be connected to earthground as well. This will divert the circuit to flow through theradiative return path, rather than have any energy attempt to travelthrough the poorly conducting return pad and back to the generator,which may cause burns on the patient.

It is noted that when there is a padded system, and the pad providessufficient conductivity under the patient, the typical monopolar circuitthat drives the current through the body and into the return pad may bea preferred method. In these cases, it may be useful to build isolationbarriers to the externally connected power source, such as the energygenerator 134002 (see FIG. 110 ). Alternatively, battery poweredinstruments may be the more ideal system for reducing the leakagecurrent that will help isolate the energy path through the conductivereturn pad.

In some aspects, the surgical system may include a detection circuitconfigured to determine the capacity of the return path pad. Thedetection circuit may then provide information as to whether it would bebetter to utilize the radiative current leakage to complete the circuit,rather than try to rely on a poorly conducting return path pad, orsimply no pad at all. The detection circuit may measure an amount ofconductivity in the return path pad. If the measure of conductivitysatisfies a predetermined threshold, the system may determine that thereturn path pad may be used to perform the surgery and provide a returnpath for the monopolar energy. If the conductivity is below thethreshold, then the detection circuit may be configured to send a signalto the system, such as at a processor in the surgical hub or themonopolar generator, that the frequency of the monopolar energy shouldbe increased drastically and the return path pad should be eliminated orat least isolated from consideration. Increasing the frequency will thencomplete the monopolar circuit through creating a radiative return path.

In some aspects, the monopolar generator may include one or more controlcircuits coupled to one or more sensors that are configured to determineif the current leakage has reached the grounding terminal of themonopolar generator. The sensor, combined with the detection circuit anda control circuit of the monopolar generator may be used to create aclosed feedback loop system that may automatically adjust the frequencyto create a sufficient return path based on high leakage current. Forexample, the detection circuit may determine if there is sufficientconductivity in the return path pad. If not, the control circuit of themonopolar generator may cause the energy generation to increase the ACfrequency. The sensor at the monopolar generator may continuouslymonitor if any radiative current leakage has reached the ground terminalof the monopolar generator, based on the increased frequency. Thecontrol circuit may gradually increase the frequency until it isdetected that the radiative current leakage has reached the groundterminal. Therefore, the surgical system may rely on a predeterminedfrequency threshold if it is determined there is no return path pad oran insufficient conductivity in the pad, or a closed feedback system maybe used to find a sufficiently high frequency that can create a returnpath through radiative coupling.

FIG. 112 is a logic flow diagram 134200 depicting a control program or alogic configuration of an example methodology that may be performed bythe surgical system utilizing monopolar energy generation to determinewhether to take advantage of parasitic capacitive coupling. Consistentwith the descriptions above, a detection circuit as part of the surgicalsystem may be configured to measure 134202 a level of conductivity inthe return path of a monopolar electrosurgical setup. The return pathmay originally be identified to go through a conductive pad, such as aSoft Megasoft Pad® or other return path conductive pad. In some cases,the conductivity of the pad may offer poor conductivity. In other cases,no pad may exist as part of the surgery setup. This may cause thepatient body to act as a short circuit of the monopolar circuit, whichwould reduce or eliminate the effectiveness of trying to apply monopolarenergy to a surgical site at the patient.

The detection circuit may determine 134204 that the measure ofconductivity falls below a predetermined threshold, indicating that thelevel of conductivity in the return path is sufficiently poor, whichprevents completion of the monopolar circuit. As a result, the surgicalsystem may cause the generator to increase 134206 the current leakage byincreasing the frequency of the alternating current in the monopolargenerator. The surgical system may instead utilize the radiative currentleakage to create a return path. When the frequency is increased, thecurrent leakage will also increase, which thereby increases the reach ofthe radiative current leakage to reach a ground plane and complete thecircuit. Thus, by increasing the frequency, the poor conductivity of thereturn path pad 134014—or even lack of any pad at all—may be subverted.In some cases, the increase in leakage may be determined based on aclosed feedback sensor system that adjusts the frequency until it isdetermined that the radiative current leakage has reached the groundterminal at the monopolar generator.

In some aspects, the surgical system also may provide an instruction toisolate 134208 any return path pads and to attach the return connectorof the monopolar generator to an earth ground. These measures may betaken to eliminate other alternative return paths that may inadvertentlycause burns at undesirable locations in the patient.

Adjustment of Compression Force Applied to Tissue Based on Proportion ofEnergy Modalities

Aspects of the present disclosure are presented for a surgicalinstrument that is situationally aware. The surgical instrument may beany suitable surgical instrument described in the present disclosure.For the sake of clarity, surgical instrument 112 is referenced. Inparticular, the surgical instrument 112 may be a bipolar combinationsurgical instrument 112 which may automatically adjust a compressionforce applied by the end effector of the surgical instrument 112 basedon a selected energy modality. In one aspect, the bipolar combinationsurgical instrument 112 may be configured to deliver energy according toa bipolar radio frequency (RF) and an ultrasonic energy modality. Morespecifically, the automatic adjustment may be based on a proportion oftwo different selected energy modalities. This automatic adjustment ofthe compression force is an example of a situational awarenesscharacteristic of the surgical instrument 112 that may improve theefficacy and quality of a surgical procedure performed with the surgicalinstrument 112. The clamp pressure applied by the end effector can beindicative of the compression force applied to tissue being treated. Asdiscussed above, selectable energy modalities include ultrasonic,bipolar or monopolar radio frequency (electrosurgical), irreversible orreversible electroporation, and microwave energy modality implemented bya generator of the surgical instrument 112. In one aspect, the twoselected energy modalities are bipolar RF energy and ultrasonic energy.Additionally or alternatively to adjusting the compression force appliedto tissue based on the selected energy modality, the compression forcemay also be adjusted based on a power parameter. The power parameter mayrefer to the relative proportion of total energy applied during asurgical procedure that is allocated between bipolar RF and ultrasonicenergy, respectively, for example.

In general, the compression force adjustment may be actively performedduring performance of a surgical procedure. Such active adjustment canmean that the clinician operating the surgical instrument 112 does notneed to manually adjust the clamp arm, waveguide or ultrasonic blade, orend effector to modify the compression force applied to tissue beingtreated in the jaws of the end effector. As described below in furtherdetail, a control circuit or generator of the situationally awaresurgical instrument 112 may automatically adjust tissue compressionforce by executing an algorithm. The algorithm is executable todetermine an appropriate compression force by considering the particularproportion or blend of the selected energy modalities. For example, therelative proportion of time spent applying each energy modality can beconsidered in determining suitable tissue compression forces to beapplied during the course of the performed surgical procedure. Therelative amplitudes of each energy modality could be considered as well.Also, each type of energy modality can correspond to a certain pressureor range of pressures, which could also change depending on otherparameters such as the power and timing of the delivered energymodality. This energy-pressure relationship can also be understood asenergy delivered and pressure existing on a spectrum together. That is,the more compression pressure that is applied, the more effective theapplication of energy to treat tissue will be. Consequently, less energymay be required when more compression pressure is applied. Energy isdelivered according to the selected energy modality.

The selected energy modalities could be applied simultaneously totissue. Alternatively, the generator may switch between providing adrive output signal according to a first energy modality such as bipolarRF and providing the drive output signal according to a second energymodality such as ultrasonic. That is, the delivery of RF can followultrasonic and vice versa. The extent of switching may be used in thealgorithm to determine a suitable automatic adjustment to tissuecompression force. For example, when the generator switches fromdelivering ultrasonic energy to bipolar RF energy, the applied tissuecompression force may be increased. When multiple energy modalities areapplied simultaneously, the relative proportion of the energy modalitiesmay be used to determine the compression force adjustment. For example,the control circuit could the proportion of ultrasonic drive signals toRF drive signals provided by the generator. As described further below,electrical or mechanical methods of adjusting tissue compression may beused and such methods may or may not involve control by the processor,control circuit, or generator as appropriate. In some aspects, thetissue compression adjustment algorithm may be stored in memory and maybe updated by an algorithm program update transmitted from thecorresponding surgical hub (e.g., surgical hub 106, 206) to the surgicalinstrument 112. In turn, the hub may receive this algorithm programupdate from a cloud computing system (e.g. cloud 104, 204). The hub mayalso store the update locally in a memory device of the hub.Additionally or alternatively, the control circuit or generator of thesurgical instrument 112 can modify the algorithm as suitable, such as bya clinician changing the parameters of the algorithm through a userinterface of the surgical instrument 112.

Mechanical methods of adjusting tissue compression force includeadjusting the waveguide or ultrasonic blade and adjusting the clamp armlinkage mechanism (e.g., linkage components of the transmissions 706a-706 e) of the surgical instrument 112. The ultrasonic blade can be forexample, an offset oval ultrasonic blade where the end effector clamparm and offset ultrasonic blade are rotatable relative to each other todefine a tissue gap distance between the end effector jaws. By adjustingthe tissue gap distance, various tissue compression forces are possible.In this way, the ultrasonic blade is adjustable to generate a smallertissue gap (and thus relatively higher compression force) when the RFenergy modality is selected and to generate a larger tissue gap (andthus relatively lower compression force) when the ultrasonic energymodality is selected. The end effector jaw members can also be adjustedfor a desired tissue gap size independently of the wave guide. Forexample, in one aspect, a clamp arm linkage mechanism is provided tochange the clamp arm actuator rod stroke according to the selectedenergy modality. The clamp arm actuator rod (e.g., articulation actuatorsuch as via output shaft of the motor 704 a, 704 b coupled to moveablemechanical elements of transmissions 706 a, 706 b) is coupled to alinkage pivot, which in turn is operationally coupled to a mechanicalselector of a surgical instrument 112.

The mechanical selector may be a mechanically actuated switch such as amomentary-action manual switch, mechanical-bail switch, capacitive touchswitch, membrane switch, or other suitable mechanical switch. Themechanical switch may be controlled by the control circuit or generatorto change the linkage pivot or linkage mechanism coupled to the endeffector clamp arm such that the clamp arm exerts different compressionforce according to the selected energy modality. As such, in oneposition of the mechanical switch, the clamp arm may be linked so thatwhen the actuator rod is actuated, relatively high compressive forcesare applied. In a second position of the mechanical switch, the clamparm may be linked so that when the actuator rod is actuated, relativelylow compressive forces are applied. In one aspect, the first positioncorresponds to the ultrasonic energy modality, while the second positioncorresponds to the bipolar RF energy modality.

Electrical methods of adjusting tissue compression force are alsopossible. For example, compression force can be automatically adjustedby the situationally aware surgical instrument 112 with the use of anelectroactive polymer (EAP). The EAP can be, for example an electric EAP(e.g., ferroelectric polymer), ionic EAP (e.g., ionomeric polymer-metalcomposite), non-ionic EAP, conductive polymer or other suitable EAP. TheEAP can be arranged in parallel with an RF energy circuit of thesurgical instrument 112, where the RF energy circuit is configured toimplement the delivery of RF energy. Accordingly, the selection of an RFenergy modality would cause current to flow through the RF energycircuit as RF energy is being delivered, which would also cause the EAPto expand. Upon expansion of the EAP, the tissue gap size decreases andresults in the application of greater compression force.

Additionally or alternatively, multiple sets of electrodes (e.g.electrodes 796, 3074 a, 3074 b) may be provided and activated accordingto a particular sequence. This type of surgical treatment can be calledhybrid activation. In hybrid activation, multiple different electrodesin the end effector are provided to perform different surgicalfunctions. For example, a first set of electrodes may be used for thesealing surgical stage and a second set of electrodes may be used forthe cutting surgical stage. To this end, a switch, filter, or othersuitable wiring is provided to route the drive signal delivered by thegenerator to one or more appropriate electrodes in the end effector. Forexample, the situationally aware surgical instrument 112 may determinethat an end effector electrode is configured for sealing rather thancutting. Consequently, an RF drive signal of relatively low voltage andhigh current may be driven through the output port of the generator tothe pre-defined sealing electrodes for sealing. Similarly, an RF drivesignal of greater power than the one used for sealing may be driven todifferent pre-defined cutting electrodes. The surgical instrument 112may determine when the shift from the sealing electrodes to the cuttingelectrodes should occur based on a measured impedance threshold. Whenthe impedance threshold is reached, the surgical instrument 112 maydetermine that a sufficiently secure seal has been created and that thecutting stage of the surgical procedure may begin. In general, the drivesignal from the generator output port is routed appropriately to thecorresponding electrode. Thus, drive signals can be routed to theappropriate treatment electrodes based on the appropriate stage of thesurgical operation being performed. Also, the tissue compression forcecan be adjusted to a suitable level based on the power, time, orproportion of the drive signal or signals that are delivered to thetissue.

In some aspects, the automatic adjustment of jaw clamp pressure may bebased on an algorithm implemented by a control circuit of the surgicalinstrument 112. As described above, the control circuit is configured toset and change various control parameters of the surgical instrument112, including clamp pressure, power delivered to treat tissue, andamplitude and frequency of waveform/drive signal output by thegenerator. Each energy modality may generally correspond to acompression force. For example, the RF (whether bipolar or monopolar)energy modality generally requires a higher extent of tissue pressurecompared to the ultrasonic energy modality. The high tissue compressionforces used for low operating temperature RF energy may be advantageousfor treating soft and connective tissue. Bipolar RF energy may requireeven higher tissue compression forces as opposed to those used inmonopolar RF energy applications. In one aspect, the compression forceadjustment algorithm may be adjusted based on a proportion of two ormore different energy modalities. That is, two energy modalities couldbe applied during a surgical procedure and the proportion of time spenton each modality could be used in an algorithm to calculate suitabletissue compression forces to be applied during the surgical procedure.Energy according to the blended multiple energy modalities could bedelivered simultaneously or substantially simultaneously. Thesituationally aware compression force adjustment algorithm may also bedynamically modified or updated via the surgical instrument 112receiving an update from a corresponding surgical hub or the cloud.

FIG. 113 is a logic flow diagram 135000 depicting a control program or alogic configuration to adjust compression force applied to tissue, basedon one or more selected energy modalities, according to a least oneaspect of the present disclosure. The compression force is adjustablefor a surgical procedure performed with a surgical instrument 112. Acontrol circuit or processor of the surgical instrument 112 (FIGS. 10-17) or hub 106 (e.g., processor 244 FIG. 8 ) determines 135002 a type oftissue (which includes any tissue described herein, but is referred toas tissue 8410 for the sake of clarity) being treated by the surgicalinstrument 112. Tissue types include, for example, connective tissue(e.g., blood vessels), muscular tissue, and bronchus tissue. Tissuetypes could be detected or determined in a number of ways, such as byusing spectral analysis of tissue bites. As discussed above, spectralanalysis of different jaw bites and device states produces differentcomplex impedance characteristic patterns (fingerprint) across a rangeof frequencies for different conditions and states. Spectroscopy may beapplied to surgical instrument 112 by exciting the tip of the ultrasonicblade of the surgical instrument 112 with a sweep of frequencies, forexample. The complex impedance characteristic patterns across a range offrequencies could be used in a model or classifier to infer tissuetypes.

Aside from inferring tissue type, tissue characteristics such as tissuethickness and stiffness may be determined, for example. Thedetermination or inference of tissue type and tissue characteristics maybe performed by the control circuit, including control circuit 500, 710,760, 3200, 3300, 3402, 3502, 3686, 3900. For the sake of clarity,control circuit 3900 is referenced in this portion of the presentdisclosure. Control circuit 3900 may comprise the processors describedabove, as appropriate, including processors 822, 1740, 1900, 3214, 3302.In one aspect, the control circuit 3900 may cause the generator to applya non-therapeutic signal to the end effector over a range offrequencies. Subsequently, the control circuit 3900 can determine thetissue impedance based on the impedance characteristic pattern derivedfrom spectral analysis of the non-therapeutic signal, as discussedabove. For the sake of clarity, generator 1100 is referred to in thisportion although the generator may be any generator described here,including generator 800, 900, 1100, 4002. Also for the sake of clarity,end effector 8400 is referenced in this portion although the endeffector may be any end effector described above, including end effector702, 752, 792, 1122. In some aspects, the generator 1100 comprises thecontrol circuit 3900; that is, the control circuit 3900 can be acomponent of the generator 1100.

Based on the tissue type and characteristic determination thesituationally aware surgical instrument 112 might infer 135002 a type ofsurgical procedure or tissue treatment. Alternatively, a suitablesurgical procedure could be manually determined or input by theclinician using the surgical instrument 112. Based on the surgicalprocedure to be performed, a first energy modality is selected 135004 bythe control circuit 3900 so that energy may be delivered by thegenerator 1100 to tissue 8410 grasped by the end effector 8400.Delivering energy may comprise outputting drive signals according to theselected energy modality (e.g., ultrasonic drive signals) or electricalsignal waveforms (e.g., current waveform determined based on LUT 2260and used to drive the ultrasonic transducer 1120 or digital waveform4300). As described above, the drive signal may have the waveform shapeof the waveform generated by the generator 1100 or control circuit 3900.Based on the surgical procedure, a second energy modality is selected135006 by the control circuit 3900. More than two energy modalitiescould also be selected by the control circuit 3900. The control circuit3900 or generator 1100 may then generate signal waveforms according toor based on the selected energy modalities or a tissue treatmentalgorithm, which could be received from the corresponding hub 106, 206or cloud 104, 204. As discussed above, energy modalities includeultrasonic, bipolar or monopolar RF, irreversible and/or reversibleelectroporation, and/or microwave energy, among others. Energymodalities can be selected depending on the type of treatment of tissuebeing performed. For example, the first and second energy modalitiescould be the ultrasonic energy modality and bipolar RF energy modality,respectively.

A tissue treatment algorithm is determined 135008. As discussed above,the surgical instrument 112 may receive 112 may receive the tissuetreatment algorithm from an external source. Additionally oralternatively, the control circuit 3900 may determine the tissuetreatment algorithm or an adjustment to the received algorithm based onthe determined tissue type and selected energy modalities from steps135002, 135004, 135006. In particular, the tissue treatment algorithmmay define parameters of the surgical treatment such as the power andtiming of the drive signal and the proportion of the energy modalities.Such parameters also may be dynamically adjusted by control circuit 3900or generator 1100 during performance of the surgical procedure. Ingeneral, the tissue treatment algorithm could be inferred by thesurgical instrument 112, received by the surgical instrument 112 throughthe corresponding surgical hub or cloud, or manually set by theclinician. The generator 1100 may infer what energy modality to applybased on feedback conditions or other sensed data received by thegenerator. For example, undeformed tissue thickness could be detectedvia a contact sensor 738 and could be used as one example characteristicin the inference of tissue type. As discussed above, different energymodalities may be advantageous for different tissue types andtreatments. For example, ultrasonic energy may be well suited fortreating smaller tissue 8410 (e.g., a small blood vessel). Inparticular, treatment with an ultrasonic blade may be appropriate forultrasonic coagulation of a small vessel.

In contrast, RF energy may be more suitable for cauterization of largertissue. To this end, as discussed above, the generator 1100 may deliverenergy with higher voltage and lower current to drive an ultrasonictransducer, with lower voltage and higher current to drive RF electrodesfor sealing tissue 8410, or with a coagulation waveform for spotcoagulation using either monopolar or bipolar RF electrosurgicalelectrodes. In one aspect, the treatment tissue algorithm may specifythe times during a surgical procedure that a particular energy modalityis applied (e.g., RF versus ultrasonic). For example, the algorithm maydefine that a mixture of RF and ultrasonic energy are delivered duringthe sealing stage of the surgical procedure and only ultrasonic energyis delivered during the cutting stage. To this end, the generator 1100may deliver ultrasonic and electrosurgical RF energy simultaneously fromits output port to provide the desired output drive signal. The mixtureof RF and ultrasonic could be applied simultaneously or substantiallysimultaneously as a blended energy modality or the generator 1100 couldbe configured to switch between delivering energy according to the RFand ultrasonic energy modalities (e.g., by switching between RFgenerator circuit 3902 and the ultrasonic generator circuit 3920 energymodalities). The treatment tissue algorithm may also specify the powerat which the energy modalities are applied. For example, as discussedabove, the waveform generator 904 and processor 902 of the generator1100 are configured to generate signal waveforms of various amplitudes(the power parameter could be set by controlling the input of the poweramplifier 1620 to set a particular waveform amplitude). The treatmenttissue algorithm can also define how the amplitude, frequency and shapeof the waveforms output by the generator 1100 changes over the course ofthe surgical procedure being performed.

The generator 1100 delivers 135010 energy to the tissue 8410 accordingto the desired tissue treatment algorithm. It may be possible to changethe tissue treatment algorithm during performance of the surgicalprocedure, such as via manual input by the clinician or data transmittedby the corresponding hub 106, 206 or cloud 104, 204. Also, as discussedabove, tissue compression force and energy delivered to the tissue 8410can vary inversely. As such, in some situations when the amplitude ofthe waveform output by the generator 1100 increases, the compressionforce may be decreased. Similarly, when the amplitude decreases, thecompression force may be increased. In other situations, the compressionforce may stay the same even as the amplitude changes. Similarly, thecompression force may change even as the amplitude stays constant. Thesituationally aware surgical instrument 112 may determine the proportionof the first energy modality versus the second energy modality. Forexample, a clock generator (e.g., clock 3330) may produce a clock signalused to track the duration that RF waveforms are applied and theduration that ultrasonic waveforms are applied during a surgicaloperation. Accordingly, the control circuit 3900 calculates 135012 theproportion of the first energy modality to the second energy modality.The control circuit 3900 may calculate 135012 the proportion based on atime or duration of the respective waveforms/drive signals of theselected energy modalities are applied as well as a frequency oramplitude of the respective waveforms. The proportion of additionalenergy modalities (e.g., a third energy modality) may also be calculated135012 if such additional modalities are used.

In one aspect, the compression force corresponding to one energymodality is relatively higher. That is, a range of compression force atwhich RF energy is applied may be greater than the range of compressionforce at which ultrasonic energy is applied. The proportion of energymodalities may be used to determine an appropriate level to set thepressure exerted by the end effector 8400. In other words, theproportion may be used to determine an appropriate tissue gap size ofthe end effector 8400 jaws. For some surgical instruments 112, the jawsof the end effector 8400 may be considered the clamp arm and theultrasonic blade or waveguide. For the sake of clarity, clamp arm 716 isreferenced in this portion although the clamp arm may be any clamp armdescribed in the present disclosure, including clamp arm 716, 766, 1140,1142 a, 1142 b. Similarly, ultrasonic blade 718 is referenced in thisportion of the present disclosure although the ultrasonic blade may beany ultrasonic blade described here, including ultrasonic blade 718,768, 1128. When trigger such as trigger 4010 is actuated, the endeffector 8400 closes such as tissue 8410 is clamped between the clamparm 716 and ultrasonic blade 718. In one aspect, the first energymodality such as the ultrasonic energy modality corresponds to a higherlevel of compression force while the second energy modality such as theRF energy modality corresponds to a lower level of compression force.The processor or control circuit may adjust 135014 tissue compressionbased on the calculated 135012 proportion. For example, a surgicalprocedure in which more ultrasonic energy and less RF energy aredelivered may result in an overall algorithmic adjustment to greatertissue compression force. Similarly, a procedure in which lessultrasonic energy and more RF energy are delivered may result in anoverall algorithmic adjustment to lesser tissue compression force.

When ultrasonic energy and RF energy are delivered simultaneously orsubstantially simultaneously, the overall proportion of ultrasonic to RFenergy may be used to determine the appropriate compression force. Moregenerally, the proportion of selected energy modalities is useable bythe control circuit 3900 to determine the adjustment. In one example, alower proportion of ultrasonic to RF energy would correspond to a highercompression force compared to the compression force corresponding to ahigher proportion. Also, the timing and power parameter of the deliveredenergy modalities during the surgical procedure may be considered forthe adjustment 135014 by the control circuit 3900. For example, ifrelatively high power RF energy is delivered at the sealing stage, thenthis may result in a smaller increase or adjustment to compression forcethan compared to a situation in which relatively high power RF energy isdelivered at the cutting stage. Moreover, the tissue compression forceadjustment may be made for only a discrete portion of the surgicalprocedure being performed. The timing and duration of the compressionforce adjustment can be determined based on the calculated proportion,selected tissue treatment algorithm, and tissue type andcharacteristics, among other possible considerations. As discussed infurther detail below, both mechanical and electrical methods areprovided to adjust the tissue gap size and consequently the appliedpressure/compression force. That is, the control circuit 3900 may usethe disclosed mechanical or electrical methods to adjust the size of thegap defined between the clamp arm 716 and ultrasonic blade 718. Audiblefeedback could be provided in the trigger 4010, for example, to indicatethat the applied compression force was adjusted. Also, the amount of theadjustment could be displayed in a display of the surgical instrument112, based on the control circuit 3900 assessing the compression forcesapplied to the clamp arm 716. The logic flow diagram 135000 of FIG. 113could also be performed by a control circuit or processor the generator1100.

FIG. 114 illustrates a mechanical method of adjusting compression forceapplied by an end effector 135100 for different treatment types,according to one aspect of the present disclosure. End effector 135100of the surgical instrument 112 is the same as or similar to other endeffectors described above, such as end effector 702, 752, 792, 1122,8400. Accordingly, end effector 135100 may comprise two jaw members. Invarious aspects, the jaw members are a clamp arm 135102 and a waveguideor blade 135104. The clamp arm 135102, which is the same or similar toclamp arm 716, 766, 1140, 1142 a, 1142 b, and the blade 135104, which isthe same or similar to ultrasonic blade 718, 768, 1128, can beconfigured to rotate. For example, as shown in FIG. 114-115B, theultrasonic blade 135104 is rotatable three hundred and sixty degrees.Additionally or alternatively, the clamp arm 135102 is also rotatablethree hundred and sixty degrees. In this way, as illustrated in FIG. 114, the ultrasonic blade 135104 can be transitioned between a horizontalor landscape orientation to a vertical or portrait orientation,including intermediate positions, which may be in between the horizontaland vertical orientations or may exceed ninety degrees.

Stated differently, the ultrasonic blade 135104 has a zero degreeorientation corresponding to a horizontal orientation and a ninetydegree orientation corresponding to a vertical orientation. With theclamp arm 135102 held in a constant or substantially constant position(shown in FIG. 114 ), the ultrasonic blade 135104 is rotatable to definea spectrum of clamp pressure. An opposite configuration is also possiblesuch that the ultrasonic blade 135104 is the constant jaw member ratherthan the clamp arm 135102. In one aspect, as the ultrasonic blade 135104rotates from zero degrees to ninety degrees, the tissue compressionforce increases from a low force to a high force. The tissue gapresulting from the zero degree orientation may be called low clamp135106 while the tissue gap resulting from ninety degrees orientationmay be called high clamp 135108. Various orientations of ultrasonicblade 135104 correspond to the same level of compression pressure. Forexample, zero degrees and one hundred and eighty degrees both correspondto low clamp 135106. FIG. 114 depicts the low clamp 135106, high clamp135108, and a third orientation 135110. The third orientation 135110depicted in FIG. 114 is slightly greater than ninety degrees, such as aone hundred and twenty degree orientation. Consequently, this thirdorientation 135110 defines a tissue gap size that is slightly smallerthan the tissue gap corresponding to high clamp 135108.

In the horizontal orientation (low clamp) 135106, the ultrasonic blade135104 may be configured for tissue sealing (e.g., coagulation orcauterization). In the vertical orientation (high clamp) 135108, theultrasonic blade 135104 may be configured for tissue cutting ordissection. As discussed above, the RF energy modality may generallycorrespond to a greater tissue compression force. Accordingly, in oneaspect, the horizontal orientation 135106 corresponds to the ultrasonicenergy modality while the vertical orientation 135108 corresponds to theRF energy modality. Other intermediate positions, including thirdorientation 135110, may be used as appropriate during the surgicaloperation. For example, an RF waveform of relatively high power and anintermediate orientation such as 60 degrees may be used when surgicaltreatment initially commences. Furthermore, the ultrasonic blade 135104orientation may change throughout a performed surgical procedureaccording to the selected 135008 tissue treatment algorithm, forexample. In another aspect, the ultrasonic blade 135104 may be an ovalshape and offset relative to the clamp arm 135102.

Other mechanical methods of adjusting compression force are disclosed.For example, the clamp arm 135102 or ultrasonic blade 135104 may bemoveable such that the end effector 135100 is configurable between aclosed configuration, an open configuration, and intermediate positionsin between to define various clamp pressures. In one aspect, amechanical switch such as a momentary-action manual switch,mechanical-bail switch, capacitive touch switch, membrane switch, orother suitable mechanical switch of the surgical instrument 112 cantransition between two positions. The control circuit 3900 may controloperation of the mechanical switch. The first and second positions maycorrespond to a first and second compression force level, which in turnmay correspond to a first and second energy modality, respectively.Thus, for example, in the first position, the mechanical switch couldcause an adjustment to the stroke or longitudinal movement of anactuator rod. The actuator rod may refer to a suitable end effector135100 actuation mechanism, such as the linkage components oftransmissions 706 a-706 e to couple motors 704 a-704 e.

In particular, the actuator rod may comprise linkage elements similar toor the same as transmissions 706 a-706 e used to transmit mechanicalenergy from the motors 704 a-704 b to actuate or close closure member714 and clamp arm 716, respectfully. The actuation stroke of theactuator rod could be adjusted by the control circuit 3900 to achievethe different compression forces of the end effector 1351000. With theadjustment caused by the first position of the mechanical switch,actuation of the actuator rod may result in a clamp arm 135102orientation corresponding to a relatively large tissue gap. Conversely,in the second position, the mechanical switch could cause a differentadjustment such that actuation of the actuator rod may result in a clamparm 135102 orientation corresponding to a relatively small tissue gap.The first position could correspond to the delivery of energy accordingto the ultrasonic modality while the second position could correspond tothe delivery of energy according to the RF modality. In one aspect, byshifting between the first and second position, the mechanical switchshifts the pivotal linkage or coupling between the actuator rod and theclamp arm 135102. In this way, the control circuit 3900 can control themechanical switch to implement adjustments to actuator stroke which inturn results in various clamp arm 135102 configurations (between andincluding open and closed configurations) that correspond to differenttissue compression forces. Other suitable mechanical means of adjustingthe actuator stroke or clamp arm configuration are also possible.

FIGS. 115A-115B illustrate a mechanical method of adjusting compressionforce applied by an end effector 135200 for different treatment types,by rotating an ultrasonic blade 135204, according to aspects of thepresent disclosure. End effector 135200 and ultrasonic blade 135204 arethe same as or similar to end effector 135100 and ultrasonic blade135104, respectively. The ultrasonic blade 135204 is rotatable between avertical and a horizontal configuration, as shown in FIGS. 115A-115B. Inone aspect, the end effector 135200 comprises a jaw member 135202 (e.g.,clamp arm 135102, 716), flexible circuit 135206 and the ultrasonic blade135204. Additionally or alternatively, the jaw member 135202 may berotatable as well. FIG. 115A depicts tissue 135208 located between thejaw member 135202 and the ultrasonic blade 135204. In the horizontalorientation shown, the ultrasonic blade 135204 is at or substantially ata zero degree orientation. Accordingly, relatively low compression forceis applied to the tissue 135208. In one aspect, the ultrasonic blade135204 is configured for tissue sealing (e.g., cauterization) in thehorizontal orientation. The ultrasonic blade 135204 also comprises sidelobe sections 135210 a, 135210 b to enhance tissue dissection anduniform sections 135212 a, 135212 b to enhance tissue sealing. Asdiscussed above, the control circuit 3900 may control rotation of thejaw member 135202 or ultrasonic blade 135204.

FIG. 115B depicts the vertical orientation in which the ultrasonic blade135204 is at or substantially at a ninety degree orientation. In anotheraspect, the ultrasonic blade 135204 is configured for tissue dissectionin the vertical orientation. The flexible circuit 135206 may includeelectrodes such that when a RF energy modality is selected, theelectrodes are configured to deliver high-frequency RF current to thetissue 135208. The electrodes may be the same or similar to electrodesdescribed in the present disclosure, such as electrodes 796, 3074 a,3074 b, 3906 a, 3906 b. Lower-frequency RF current is also possible.When the RF energy modality is selected, the ultrasonic blade 135204 mayact as the electrical ground for the RF waveform output from thegenerator 1100. That is, the RF electrodes (e.g., RF electrodes 796)could be coupled to the positive pole while the ultrasonic blade 135204is coupled to the negative or return pole. In some configurations, thepolarity may be reversed such that the RF electrodes 796 are coupled tothe negative pole and the ultrasonic blade 135204 is coupled to thepositive pole. In one aspect, when both the RF and ultrasonic energymodalities are selected, the RF current conducted by the electrodes 796is used to seal the tissue 135208 and the ultrasonic blade 135204 isused to dissect tissue based on ultrasonic vibrations propagatingthrough ultrasonic blade 135204. As discussed above with respect to FIG.115A-115B, other intermediate orientations of the rotatable ultrasonicblade 135204 may also be possible, so that additional levels ofdifferent compression forces may be adjusted and applied to tissue135208 as appropriate.

Electrical methods of adjusting compression force between treatmenttypes are also disclosed. For example, a suitable EAP may be used as anelectrostatic actuator for changing tissue gap size. EAPs are voltageactivated elastomers which can be electronic EAPs such aselectrostrictive elastomers and dielectric electroactive polymers(DEAPs) or ionic EAPs such as ionic polymer metal composites (IPMCs).EAPs have an electromechanical thickness or other strain that is inducedby electrostatic forces. Stated differently, when a voltage is appliedto an EAP, the EAP bends, contracts, or expands. An EAP actuator may beused in the surgical instrument 112 to change the tissue gap size forchanging the applied compression forces based on application of avoltage potential to the EAP. The EAP actuator may be controlled by thecontrol circuit 3900. For example, the EAP may be configured to expand,which causes the application of more pressure on the blade 135204 orelectrodes 796 positioned in the end effector 135200. To this end, theEAP may be positioned in the end effector 135200 between the powersource (e.g., generator) and RF electrodes 796. For example, the EAPcould be part of the flexible circuit 135206. In this way, as an RFwaveform is output from the generator 1100, voltage is applied to theEAP, which causes the EAP to expand and apply a force on the RFelectrodes such that the tissue gap size decreases. In general, the EAPmay expand as the generator 1100 delivers energy according to theselected energy modalities.

Additionally or alternatively, when the EAP expands, this causes a forceto be applied to the blade 135200 such that the tissue gap sizedecreases. Conversely, the EAP may be positioned and configured suchthat electrostatic actuation causes the EAP to contract, which reducesthe compression force applied to the tissue. The change in the size ofthe EAP may be proportional to the voltage used for EAP actuation andthe adjustment to compression force that results. In one aspect, the EAPmay also be positioned in the shaft of the surgical instrument 112, forexample, such that electrostatic actuation causes the EAP to exertfurther force on the clamp arm 135102 or the end effector 135200.Similarly, the EAP could be configured to remove or reduce force appliedby the clamp arm 135102. In this way, the EAP actuator may be employedto change the end effector configuration, which spans between the openand closed configurations. In general, the EAP could be provided suchthat the control circuit 3900 can increase compression force as agreater proportion of energy is delivered according to the RF energymodality. Similarly, the EAP could be used to adjust pressure as anotherenergy modality such as the ultrasonic energy modality is selected. TheEAP could be part of the flexible circuit 135206, for example.

In general, the end effector 135200 of the surgical instrument 112 maycomprise an ultrasonic blade 135200 and a clamp arm 135102, which mayfunction as the first and second jaws of the end effector 135200. Theend effector 135200 is configured to clamp tissue therebetween the jaws,fire fasteners through the clamped tissue 135208, sever the clampedtissue 135208, and grasp tissue 135208 for application of energyaccording to the selected energy modality. Moreover, the force appliedto the tissue 135208 by the end effector 135200 may be measured by thestrain gauge sensor 474, such as by measuring the amplitude or magnitudeof the strain exerted on a jaw member of the end effector 135200 duringa clamping operation. As discussed above, energy may be deliveredaccording to multiple energy modalities such as RF and ultrasonicenergy, in conjunction to achieve surgical sealing, cutting, andcoagulation functions. Although energy from the generator 1100 could bedelivered simultaneously such as through simultaneously delivering oroutputting waveforms from the generator 1100 to the RF electrodes 796and the ultrasonic transducer 1120 in conjunction, such energy deliverycan also switch between different energy modalities.

FIG. 116 shows a diagram 135300 illustrating switching between activeelectrodes of an end effector 135200 according to one aspect of thepresent disclosure. Again, the electrodes may be the same or similar toelectrodes 796, 3074 a, 3074 b, 3906 a, 3906 b. As discussed above, thesituationally aware surgical instrument 112 may infer or determine anappropriate tissue treatment algorithm for the surgical procedure beingperformed. The tissue compression force adjustment is made based on thisalgorithm and the proportion of selected energy modalities. In addition,the tissue compression force adjustment may be made based on switchingfrom a passive electrode to an active electrode for treatment, as shownin FIG. 116 . For example, the situationally aware surgical instrument112 may detect a selected function of the surgical instrument 112 suchas sealing or cutting. Based on the selected function, a switch, filter,or other suitable wiring such as a relay or transistor may be providedto control routing the waveform (e.g., waveform 4300) output by thegenerator 1100 to an appropriate electrode. FIG. 116 depicts the endeffector 135200 with a first set of two treatment electrodes “A” 135302and a second set of two treatment electrodes “B” 135304, both of whichmay alternate between active or passive states. The two sets oftreatment electrodes 135302, 135304 are provided on both jaws of the endeffector 135200. Based on which treatment electrode is active orpassive, the applied compression force may be adjusted.

In one aspect, the “A” electrodes 135302 are configured for the sealingstage and the “B” electrodes 135304 are configured for the cuttingstage. These configurations could be used by the surgical instrument 112to determine if and what compression force adjustment is required whenan energy modality is selected. For example, when the “A” electrodes135302 become passive while the “B” electrodes 135304 become active, thesurgical instrument 112 may adjust the compression force. This could bean adjustment to decrease the compression force, such as because theadditional power delivered during the cutting stage might not require asmuch corresponding compression force. The extent of the adjustment candepend on the proportion of one energy modality (e.g., RF) to another(e.g., ultrasonic) as calculated throughout the duration of theperformed surgical operation. In one aspect, the switch is configured toroute the output energy by the generator 1100 to the sealing electrodes“A” 135302 while the surgical instrument 112 is used for coagulation.Multiple impedance thresholds 135306, 135308 may be provided, which areindicated on the impedance graph (Z) 135312 in FIG. 116 as dotted lines.FIG. 116 shows that when threshold 135306 is crossed at point 135310,the crossing may indicate when optimal tissue coagulation is complete.That is, when the measured tissue impedance reaches point 135310, it maybe determined that a sufficiently secure tissue seal has formed.

As discussed above, impedance may be measured by dividing the output ofthe voltage sensing circuit and the current sensing circuit or by usingspectral analysis, for example. When coagulation is complete, the switchmay transition to a second position to route a different waveform fromthe generator 1100, in which the amplitude of the different waveform israised relative to the waveform used for coagulation. The differentwaveform may be applied for surgical cutting rather than forcoagulation. Accordingly, the switch may route this different waveformto the “B” electrodes 135304. As can be seen in the power graph 135314of FIG. 116 , the amplitude of the waveform is greater than theamplitude of the coagulation waveform. Although the power levels shownin power graph 135314 are constant, dynamic power levels may be used aswell. As discussed above, the increase in power from “A” electrodes135302 to “B” electrodes 135304 may trigger an adjustment to tissuecompression, which may be determined based on the proportion of oneselected energy modality to another. In another aspect, the surgicalcutting achieved via the “B” electrodes 135304 is a knifeless cutting.Although the energy modality selected for the tissue treatmentillustrated in FIG. 116 may be RF, other energy modalities may be usedfor such treatment and over the course of a performed surgicaloperation.

Advanced RF Energy Device Including Nerve Stimulation Signal withTherapeutic Waveforms

As disclosed above, in some surgical procedures, a medical professionalmay employ an electrosurgical device to seal or cut tissues such asblood vessels. Such devices effect a medical therapy by passingelectrical energy, for example current at radiofrequencies (RF), throughthe tissue to be treated. Some electrosurgical devices are termedbipolar devices in that both an electrode to source the electricalenergy (the active electrode) and a return electrode are housed in thesame surgical probe. It will be appreciated that a surgical probe maycomprise a handpiece or a robotically controlled instrument or acombination thereof.

Alternative devices may be termed monopolar devices. In such devices,only the active electrode is housed in the surgical probe. Theelectrical current entering the patient's tissue may return to theelectrical energy generator via an electrical path through the gurney onwhich the patient reposes or through a specific return electrode pad. Insome aspects, the patient may repose on the electrode pad, or theelectrode pad may be placed on the patient at a location close to thesurgical site where the surgical probe is deployed. It may be recognizedthat the current path through a patient undergoing a procedure using amonopolar device may be less well characterized than the current paththrough a patient undergoing a procedure using a bipolar device.Consequently, some non-target tissue may be inadvertently cauterized,cut, or otherwise damaged by a monopolar electrosurgical device. Suchunintended injury to excitable tissue may result in the patientexperiencing muscle weakness, pain, numbness, paralysis and/or otherundesired outcomes.

It is therefore desirable that a monopolar electrosurgical deviceincorporate features to determine if the device is close enough toexcitable tissue to cause inadvertent injury. Such features may be usedby one or more subsystems of the electrosurgical device as a basis fornotifying the medical professional of the proximity of such tissue tothe monopolar electrode. Additionally, such features may be used by oneor more subsystems of an intelligent electrosurgical device to reduce oreliminate the amount of therapeutic energy delivered to tissue deemed toclose to non-target excitable tissue. In some intelligent medicaldevices that combine electrosurgical (RF) with ultrasonic therapeuticmodes, features to determine if the device is close enough to excitabletissue to cause inadvertent injury when the device is operating in theelectrosurgical (RF) mode may result in the device switching to theultrasonic mode.

Electrosurgical devices for applying electrical energy to tissue inorder to treat and/or destroy the tissue are also finding increasinglywidespread applications in surgical procedures. An electrosurgicaldevice typically includes a surgical probe, an instrument having adistally-mounted end effector (e.g., one or more electrodes). The endeffector can be positioned against the tissue such that electricalcurrent is introduced into the tissue. Electrosurgical devices can beconfigured for bipolar or monopolar operation. During bipolar operation,current is introduced into and returned from the tissue by active andreturn electrodes, respectively, of the end effector. During monopolaroperation, current is introduced into the tissue by an active electrodelocated at a distal end of the surgical probe and returned through areturn electrode (e.g., a grounding pad) separately located on apatient's body. Heat generated by the current flowing through the tissuemay form hemostatic seals within the tissue and/or between tissues andthus may be particularly useful for sealing blood vessels, for example.The end effector of an electrosurgical device also may include a cuttingmember that is movable relative to the tissue and the electrodes totransect the tissue.

FIG. 117 depicts a typical monopolar electrosurgical system 136000. Theelectrosurgical system 136000 can include a controller 136010, agenerator 136012, an electrosurgical instrument 136015, and a return pad136020 which includes one or more return electrodes. Typically, thegenerator 136012 may source an electrical signal to the electrosurgicalinstrument 136015 along a first conducting electrical path 136017 andmay receive a return signal from the one or more return electrodes alonga second conducting electrical path 136023. FIG. 117 depicts an exampleof a health care professional 136025 treating a patient 136027 using anelectrosurgical instrument 136015 such as an active monopolar electrode.

FIG. 118 is a schematic block diagram of the patient and electricalcomponents depicted in FIG. 117 . The generator 136012 may be a separatecomponent from the controller 136010 or the controller 136010 mayinclude the electrical generator 136012. The controller 136010 maycontrol the operation of the generator 136012, including controlling anelectrical output thereof. As disclosed below, the controller 136010 maycontrol one or more output waveforms of the electrical generator 136012including the control of a variety of characteristics includingamplitude characteristics, frequency characteristics, and phasecharacteristics of the output signal of the electrical generator 136012.The controller 136010 may further receive signals from any number ofadditional components including, without limitation, manual controlactuators (switches, push buttons, slides, and similar), sensors, ordata signals transmitted by any number of communication devices,computers, smart surgical devices, and imaging systems. The controller136010 may be composed of any type or types of computer processordevices, one or more memory components (static and/or dynamic memorycomponents), and communication components configured to transmit and/orreceive data signals (analog or digital) as may be required for thefunctioning of the controller. The memory components of the controller136010 may contain one or more instructions that, when read by the oneor more computer processor devices, may direct the operation of thecontroller. Examples of such instructions and their intended results aredisclosed below.

Electrical energy may be sourced by the electrical generator 136012 andreceived by a surgical instrument 136015 such as an active monopolarelectrode. In some aspects, the active electrode may be in electricalcommunication with an electrical source terminal of the electricalgenerator 136012 to receive the electrical energy. In some aspects, thesurgical instrument 136015 may receive an electrical signal over a firstconducting electrical path 136017 such as a wire or other cabling.

During the procedure, the patient 136027 may lie supine on a return pad136020. The return pad 136020 may be in electrical communication withthe electrical generator 136012 via an electrical return terminal, andthe electrical energy sourced into the patient 136027 by theelectrosurgical instrument 136015, such as an active electrode, may bereturned to the electrical generator 136012 through the return pad136020. In some aspects, the return pad 136020 may be in electricalcommunication with the electrical return terminal over a secondconducting electrical path 136023, such as a wire or other cabling.

In some aspects, the generator 136012 may supply alternating current atradiofrequency levels to the electrosurgical instrument 136015. In somealternative aspects, the electrosurgical instrument 136015 may alsoincorporate features for ultrasonic therapeutic modes, and the generator136012 may also be configured to generate power to drive one or moreultrasonic therapeutic components. The electrosurgical instrument136015, which typically includes an electrode tip (i.e., an activeelectrode) which can be positioned at a target tissue of a patient136027, receives the alternating current from the generator 136012 anddelivers the alternating current to the target tissue via the electrodetip. The alternating current received by the electrode tip may be fromthe generator 136012 via a first conducting electrical path 136017. Thealternating current is received at the target tissue, and the resistancefrom the tissue creates heat which provides the desired effect (e.g.,sealing and/or cutting) at the surgical site. The alternating currentreceived at the target tissue is conducted through the patient's bodyand ultimately is received by the one or more return electrodes of thereturn pad 136020. The alternating current received by the return pad136020 may be conducted back to the generator via a second conductingelectrical path 136023 to complete the closed path followed by thealternating current. The one or more return electrodes are configured tocarry the amount of current introduced by the electrode tip. The returnpad 136020 may be attached to the patient's body or may be separated asmall distance from the patient's body (i.e., capacitive coupling). Thealternating current received by the one or more return electrodes ispassed back to the generator 136012 to complete the closed path followedby the alternating current.

For an electrosurgical system 136000 which utilizes capacitive couplingto complete the current path between the patient's body and the returnelectrode, the patient's body effectively acts as a first capacitiveplate of a capacitor and the return electrode pad effectively acts as asecond capacitive plate of a capacitor.

In some aspects, the return pad 136020 may include a single returnelectrode which incorporates an array of multiple sensing devices. Insome alternative aspects, the return pad 136020 may include an array ofreturn electrodes, where an array of sensing devices may be incorporatedinto the array of return electrodes. In one non-limiting example, thereturn pad 136020 may include multiple return electrodes in which eachof the return electrodes includes a sensing device.

By incorporating an array of sensing devices into the return electrodepad 136020, the sensing devices may be used to detect either a nervecontrol signal applied to the patient or a movement of an anatomicalfeature of the patient resulting from an application of the nervecontrol signal. The sensing devices may include, without limitation, oneor more pressure sensors, one or more accelerometers, or combinationsthereof. In some non-limiting aspects, a sensing device may beconfigured to output a signal indicative of the detected nerve controlsignal and/or the detected movement of an anatomical feature of thepatient. Using Coulomb's law and the respective locations of the activeelectrode, the patient's body and the sensing devices, the detectednerve control signal and/or movement of an anatomical feature of thepatient can be analyzed to determine the location of a nerve within thepatient's body.

In some aspects, for example as depicted in FIG. 120 , a return pad136120 may include a plurality of electrodes 136125 which can becapacitively coupled to the patient's body and collectively areconfigured to carry the amount of current introduced into the patient'sbody by the electrosurgical instrument. For this capacitive coupling,the patient's body effectively acts as one plate of a capacitor andcollectively the plurality of electrodes 136125 of the return pad 136120effectively act together as the other plate of the capacitor. A moredetailed description of capacitive coupling can be found, for example,in U.S. Pat. No. 6,214,000, titled CAPACITIVE REUSABLE ELECTROSURGICALRETURN ELECTRODE, issued Apr. 10, 2001 and in U.S. Pat. No. 6,582,424,titled CAPACITIVE REUSABLE ELECTROSURGICAL RETURN ELECTRODE, issued Jun.24, 2003, the entire contents of which are each incorporated herein byreference and in their respective entireties.

FIG. 118 illustrates a plurality of electrodes 136125 a-d of the returnpad of FIG. 117 , in accordance with at least one aspect of the presentdisclosure. Although four electrodes 136215 a-d are shown in FIG. 118 ,it will be appreciated that the return pad 136120 may include any numberof electrodes 136125. For example, according to various aspects, thereturn pad 136120 may include two electrodes, eight electrodes, sixteenelectrodes, or any number of electrodes that may be fabricated in thereturn pad 136120. It should be recognized that the number of electrodesmay be an even integer or an odd integer. Also, although the individualelectrodes 136125 a-d are shown in FIG. 118 as being substantiallyrectangular, it will be appreciated that the individual electrodes canbe of any suitable shape.

The electrodes 136125 a-d of the return pad 136120 may serve as thereturn electrodes of the electrosurgical system of FIGS. 117 and 118 ,and can also be considered to be segmented electrodes as the electrodes136125 a-d can be selectively decoupled from the patient's body and/orthe generator. In some aspects, the electrodes 136125 a-d of the returnpad 136120 can be coupled together to effectively act as one largeelectrode. For example, according to various aspects, each of theelectrodes 136125 a-d of the return pad 136120 can be connected byrespective conductive members 136130 a-d to inputs of a switching device136135 as shown in FIG. 119 . When the switching device 136135 is in anopen position, as shown in FIG. 119 , the respective electrodes 136125a-d of the return pad 136120 are decoupled from one another as well asfrom the patient's body and/or the generator. In contrast, when theswitching device 136135 is in a closed position, the respectiveelectrodes 136125 a-d of the return pad 136120 are coupled together toeffectively act as a single large electrode. It may be recognized thatdiffering combinations of electrodes 136125 a-d may be coupled togetherby the switching device 136135 to form any group or groups ofelectrodes. For example, if a patient is disposed in a supine positionon the return pad 136120 with the patient's head proximate to theswitching device 136135, electrodes 136125 a and 136125 c may be coupledtogether and electrodes 136125 b and 136125 d may be coupled togetherthereby sensing electrical currents flowing through the lower torso andupper torso, respectively. Alternatively, if a patient is disposed in asupine position on the return pad 136120 with the patient's headproximate to the switching device 136135, electrodes 136125 a and 136125b may be coupled together and electrodes 136125 c and 136125 d may becoupled together thereby sensing electrical currents flowing through theright torso and left torso, respectively.

The switching device 136135 can be controlled by a processing circuit(e.g., a processing circuit of the generator of the electrosurgicalsystem, of a hub of an electrosurgical system, etc.). For purposes ofsimplicity, the processing circuit is not shown in FIG. 119 . Accordingto various aspects, the switching device 136135 can be incorporated intothe return pad 136120. According to other aspects, the switching device136135 can be incorporated into the second conducting electrical path ofthe electrosurgical system of FIGS. 117 and 118 . The return pad 136120can also include a plurality of sensing devices.

FIG. 120 illustrates an array of sensing devices 136140 a-d of thereturn pad in accordance with at least one aspect of the presentdisclosure. According to various aspects, the number of sensing devices36140 a-d may correspond to the number of electrodes 36125 a-d such thatthere is one sensing device for each electrode (for example, sensingdevice 36140 a with electrode 136125 a, sensing device 36140 b withelectrode 136125 b, sensing device 36140 c with electrode 136125 c, andsensing device 36140 d with electrode 136125 d). Each sensing device36140 a-d may be mounted to or integrated with a corresponding electrode136125 a-d, respectively. However, although the number of sensingdevices 36140 a-d associated with the corresponding electrodes 136125a-d may correspond to the number of electrodes, it will be appreciatedthat the return pad may include any number of sensing devices. Forexample, for aspects of the return pad which include sixteen electrodes,the return pad may only include four or eight sensing devices. Althoughthe sensing devices 136140 a-d are shown in FIG. 120 as being centeredon the corresponding electrodes 136125 a-d, respectively, it will beappreciated that the sensing devices 136140 a-d can be positioned on anyportion of the corresponding electrodes 136125 a-d. It may be furtherunderstood that the position of a particular sensing device on aparticular electrode is independent of a position of any other sensingdevice on its respective electrode.

The sensing devices 136140 a-d are configured to detect a monopolarnerve control signal applied to the patient and/or a movement of ananatomical feature of the patient (e.g., a muscle twitch) resulting fromapplication of the nerve control signal. The monopolar nerve controlsignal may be applied by the surgical instrument of the electrosurgicalsystem of FIGS. 117 and 118 , or may be applied by a different surgicalinstrument which is coupled to a different generator. Each sensingdevice 136140 a-d may include, for example, a pressure sensor, anaccelerometer, or combinations thereof, and is configured to output asignal indicative of the detected nerve control signal and/or thedetected movement of an anatomical feature of the patient. In somenon-limiting examples, a sensing device composed of a pressure sensormay include for example, a piezoresistive strain gauge, a capacitivepressure sensor, an electromagnetic pressure sensor, and/or apiezoelectric pressure sensor either alone or in combination. In somenon-limiting examples, a sensing device composed of an accelerometer mayinclude, for example, a mechanical accelerometer, a capacitiveaccelerometer, a piezoelectric accelerometer, an electromagneticaccelerometer, and/or a microelectromechanical system (MEMS)accelerometer either alone or in combination. The respective outputsignals of the respective sensing devices 136140 a-d may be in the formof analog signals and/or digital signals.

Using Coulomb's law and the respective locations of the active electrodeof the surgical instrument, the patient's body and the respectivesensing devices, the respective output signals of the respected sensingdevices 136140 a-d, which are indicative of a detected nerve controlsignal and/or movement of an anatomical feature of the patient, can beanalyzed to determine the location of a nerve within the patient's body.Coulomb's law states that E=K(Q/r²), where E is the threshold currentrequired at a nerve to stimulate the nerve, K is a constant, Q is theminimal current from the nerve stimulation electrode and r is thedistance from the nerve. The further the nerve stimulation electrode isfrom the nerve (r increases), the current required to stimulate thenerve is proportionately greater. Thus, the amount of stimulation of anexcitable tissue as measured by a sensing device 136150 a-d may berelated to the distance of the nerve stimulation electrode to theexcitable tissue at constant current stimulation. In some aspects, anoutput signal of a sensing device 136140 a-d may also be dependent onthe distance of the excitable tissue to the sensing device 136140 a-d.It may be recognized that multiple sensing devices 136140 a-d may beused to triangulate the position of an electrically stimulated excitabletissue based on the geometry and position of the multiple sensingdevices 136140 a-d. A constant current stimulus can thus be utilized toestimate the distance from the nerve stimulation electrode to the nerve.Alternatively, current stimulus composed of varying amounts of currentmay be used to improve the determination of the position of theexcitable tissue through the triangulation method associated withmultiple sensing devices 136140 a-d. In general, the respectivestrengths of the output signals of the respective sensing devices areindicative of how close or far the respective sensing devices are fromthe stimulated nerve of the patient.

According to various aspects, the analysis of the respective outputsignals of the respective sensing devices can be performed by aprocessing circuit of the generator of the electrosurgical system ofFIGS. 117 and 118 , by a processing circuit of a nerve monitoring systemwhich is separate from the generator of the electrosurgical systemthereof, by a processing circuit of a hub of an electrosurgical system,etc. The analysis can be performed in real time or in near-real time.According to various aspects, the respective output signals serve asinputs to a monopolar nerve stimulation algorithm which is executed bythe processing circuit.

As shown in FIG. 120 , according to various aspects, the output signalsof the respective sensing devices 136140 a-d can be input into amultiple input—single output switching device 136137 (e.g., amultiplexer) via respective conductive members 136142 a-d, respectively.By controlling the selection signals S0, S1 to the multiple input—singleoutput switching device 136137, the multiple input—single outputswitching device 136137 can be controlled to output only one of theoutput signals of the respective sensing devices 136140 a-d at a timefor the above-described analysis. As one non-limiting example, withreference to FIG. 120 , by setting the selection signals S0, S1 to 0,0,the output signal from the sensing device 136140 c can be output by themultiple input—single output switching device 136137 for analysis by theapplicable processing circuit. In another non-limiting example, settingthe selection signals S0, S1 to 0,1, the output signal from the sensingdevice 136140 a can be output by the multiple input—single outputswitching device 136137 for analysis by the applicable processingcircuit. Similarly, by setting the selection signals S0, S1 to 1,0, theoutput signal from the sensing device 136140 d can be output by themultiple input—single output switching device 136137 for analysis by theapplicable processing circuit. And, by extension, by setting theselection signals S0, S1 to 1,1, the output signal from the sensingdevice 136140 b can be output by the multiple input—single outputswitching device 136137 for analysis by the applicable processingcircuit.

The selection signals S0, S1 can be provided to the multipleinput—single output switching device 136137 by a processing circuit suchas, as non-limiting examples, a processing circuit of the generator ofthe electrosurgical system of FIGS. 117 and 118 , a processing circuitof a nerve monitoring system which is separate from the generator of theelectrosurgical system, by a processing circuit of a hub of anelectrosurgical system, and similar. For purposes of simplicity, theprocessing circuit is not shown in FIG. 120 . By providing the variousselection signals at a fast enough rate, the output signals of therespective sensing devices 136125 a-d can effectively be scanned at arate which allows for the timely analysis of all of the output signalsof the respective sensing devices 136125 a-d to determine the positionof the stimulated nerve.

According to various aspects, the multiple input—single output switchingdevice 136137 can be incorporated into the return pad. According toother aspects, the multiple input—single output switching device 136137can be incorporated into the second conducting electrical path 136023 ofthe electrosurgical system 136000 of FIG. 117 .

The control of the multiple input—single output switching device 136137as disclosed in FIG. 120 may be in the context of a four input-oneoutput switching device, corresponding to the four sensing devices136140 a-d depicted in FIG. 120 . It will be appreciated that foraspects in which there are more than four sensing devices (e.g., sixteensensing devices), the output signals of the more than more than foursensing devices may serve as inputs to a multiple input —single outputswitching device having more than two selection signals (e.g., S0, S1,S2 and S3).

For aspects where the output signals of the sensing devices (for example136140 a-d are analog signals, the output of the multiple input—singleoutput switching device 136137 can be converted into a correspondingdigital signal by an analog-to-digital converter 136145 prior to theperformance of the analysis of the output signals by the applicableprocessing circuit.

Returning to FIG. 117 , according to various aspects, the detection ofthe nerve control signal and/or the movement of an anatomical feature ofthe patient by the sensing devices can be performed while the electrodes136125 a-d of the return pad 136120 are coupled to one another or whilethe electrodes 136125 a-d are uncoupled from one another. For example,with regard to performing the detection when the respective electrodes136125 a-d of the return pad 136120 are uncoupled from one another,after positioning the patient on the operating table but before startinga surgical procedure, the return pad 136120 can be placed in a “sensingmode” by controlling the switching device 136135 to uncouple therespective electrodes 136125 a-d of the return pad 136120 from oneanother. While the respective electrodes 136125 a-d are uncoupled fromone another, a nerve and/or a nerve bundle can be stimulated with anelectrosurgical instrument as described above, and the respective outputsignals of the sensing devices of the return pad 136120 can be analyzedas described above to identify where the nerve, nerve bundle and/ornerve nexuses associated therewith are located. The locations of thenerve, nerve bundle and/or nerve nexuses may be input into a monopolarnerve stimulation algorithm profile. Once the locations of the nerve,nerve bundle and/or nerve nexuses are input into the monopolar nervestimulation algorithm profile, the locations of the nerve, nerve bundleand/or nerve nexuses may be effectively isolated from the capacitiveoperation of the electrodes of the return pad 136120. The locations ofthe nerve, nerve bundle and/or nerve nexuses may be used as sensingnodes of the monopolar nerve stimulation algorithm profile to inform thesurgeon as the surgeon approaches a nerve and/or a nerve bundle whileperforming a tissue cutting procedure. According to various aspects, thesurgeon may be informed of the nearby location of the nerve and/or nervebundle via an audible warning, a visual warning, a tactile (such asvibratory) warning, etc.

Returning to FIG. 118 , with regard to performing the detection when therespective electrodes of the return pad 136015 are coupled with oneanother, according to various aspects, the generator 136012 of theelectrosurgical system can generate a high frequency waveform (thealternating current at radio frequency) which may be modulated on acarrier wave having a sufficiently low frequency to stimulate a nerve ofthe patient. This modulation may allow for the sensing of the nervecontrol signal and/or the movement of an anatomical feature concurrentlywith the capacitive coupling of the respective electrodes of the returnpad 136020 with the patient's body 136027. By applying a specificwaveform to the patient 136027 and sensing a specific response, there isa high level of confidence that the movement of the anatomical featuremay be correlated with the applied waveform and not due to randompatient motion. The modulation can be adjusted over time to stimulatedifferent nerve sizes. According to various aspects, the modulation canbe varied in amplitude over time in order to allow the applicableprocessing circuit to determine the distance the nerve and/or nervebundle is from the signal without having to constantly stimulate thenerve and/or nerve bundle.

The electrical energy applied by a surgical probe of an electrosurgicaldevice to the tissue may be in the form of radio frequency (RF) energythat may be in a frequency range described in EN60601-2-2:2009+A11:2011, Definition 201.3.218—HIGH FREQUENCY. Forexample, the frequencies in monopolar RF applications are typicallyrestricted to less than 5 MHz. Frequencies above 200 kHz can betypically used for MONOPOLAR applications in order to avoid the unwantedstimulation of nerves and muscles which would result from the use of lowfrequency current. Lower frequencies may be used for BIPOLAR techniquesif the RISK ANALYSIS shows the possibility of neuromuscular stimulationhas been mitigated to an acceptable level. Normally, frequencies above 5MHz are not used in order to minimize the problems associated with HIGHFREQUENCY LEAKAGE CURRENTS. However, higher frequencies may be used inthe case of BIPOLAR techniques. It is generally recognized that 10 mA isthe lower threshold of thermal effects on tissue.

It may be recognized that an electrosurgical device may take advantageof the response of excitable tissue to electrical frequencies below 200kHz in order to determine if such excitable tissue is sufficientlyproximate to the end effector of the electrosurgical device to bepotentially damaged thereby. FIG. 121 illustrates an RF signal 136210that may be used in an electrosurgical device to cut or cauterizetissue. Such an RF signal 136210 may be termed a therapeutic signalbecause it has a frequency that may effect a therapeutic result such ascauterizing or cutting tissue. For purely illustrative purposes, thex-axis may represent time wherein each division represents 10 μsecs, andthe y-axis (amplitude) has an arbitrary value. The RF signal 136210depicted in FIG. 121 may therefore have a frequency of about 1 MHz. Itmay be understood that an RF therapeutic signal may have any frequency,amplitude, and/or phase characteristics sufficient to effect atherapeutic application such as sealing, cauterizing, ablating, orcutting a tissue.

FIG. 122 depicts a signal 136220 that may be used to stimulate excitabletissue such as nerves or muscle. Again, solely for illustrativepurposes, the signal 136220 depicted in FIG. 122 may extend over about20 μsecs, and, if repeated, would constitute a waveform having afrequency of about 50 kHz. Such an electrical signal 136220 may betermed a stimulating signal because it has a frequency that may simulateexcitable tissues such as nerve or muscle tissue. It may be understoodthat a waveform of a stimulating signal may differ from the signal136220 presented in FIG. 122 in any aspect such as duration, frequency,or amplitude. In general, a stimulating signal 136220 may have anyappropriate waveform or amplitude while having a frequency within arange that is capable of stimulating such excitable tissue. Asindicated, such waveforms as depicted in FIGS. 121 and 122 areillustrative only. In one alternative example, a therapeutic RF signalmay have a frequency of about 330 kHz and a waveform to stimulateexcitable tissue may have a frequency of about 2 kHz.

It may be understood that an intelligent electrosurgical device may beconfigured to emit either a therapeutic signal or a stimulating signalor a combination thereof. FIGS. 123A-123C present examples ofcombinations of therapeutic signals and stimulating signals. Theelectrical generator may source an output current composed of any numberor combination of characteristics of the therapeutic signal andcharacteristics of a tissue stimulating signal. Non-limiting examples ofcharacteristics of a therapeutic signal may include a therapeutic signalfrequency, a therapeutic signal amplitude, and a therapeutic signalphase. Non-limiting examples of characteristics of a tissue stimulatingsignal may include a stimulating signal frequency, a stimulating signalamplitude, and a stimulating signal phase. It may be recognized that atherapeutic signal may be characterized by any number of frequencies,phases, and amplitudes. Additionally, it may be recognized that a tissuestimulating signal may be characterized by any number of frequencies,phases, and amplitudes. In some aspects, the controller may beconfigured to control an electrical generator to provide an electricaloutput composed of a combination or combinations of characteristics of atherapeutic signal and characteristics of a tissue stimulating signal.

FIG. 123A depicts a non-limiting example of a first combination signal136230 composed of a first therapeutic signal 136212 a, a stimulatingsignal 136222, and a second therapeutic signal 136212 b. As depicted,one or more stimulating signals (such as signal 136220, FIG. 122 ) mayalternate with one or more therapeutic signals (such as signal 136210,FIG. 121 ). It may be understood that the length of time for theapplication of the one or more therapeutic signals (such as 136212 a,b)may be arbitrary and may depend on the length of time that a medicalprofessional may wish to apply it. It may also be understood that thestimulating signal 136222 may be transmitted at any time during theapplication of a therapeutic signal. It may be further understood thatone or more zero-amplitude signals may be interspersed between one ormore therapeutic signals and one or more stimulating signals. Multiplestimulating signals may be transmitted in succession before a subsequenttherapeutic signal is transmitted.

FIG. 123B presents a non-limiting example of a second combination signal136240 of a therapeutic signal and a stimulating signal. In FIG. 123B,the stimulating signal (136220 depicted in FIG. 122 ) may be used tomodulate the amplitude of the therapeutic signal (136210 depicted inFIG. 121 ). In some aspects, the stimulating signal 136220 may beapplied directly to an amplitude modulation circuit to modulate theamplitude of a therapeutic signal 136210. In alternative aspects, thestimulating signal 136220 may be offset and scaled before being used tomodulate the amplitude of the therapeutic signal 136210. As an example,the stimulating signal 136220 in FIG. 122 may be offset by +4.5 V andthe resulting signal may be scaled by 4.5 V so that the amplitude of thetherapeutic signal 136210 is modulated by a positive-valued modulationsignal that may range in value from about 0.1V to about 2V. One mayreadily recognize that any simple transformation of a stimulating signal136220 may be used to modulate the amplitude of a therapeutic signal136210. It may be recognized that the amplitude of the therapeuticsignal 136210 may be modulated by the stimulating signal 136220 at anytime or for any number of times during the application of thetherapeutic signal. The amplitude of the therapeutic signal 136210 maybe modulated in the same manner over the course of multiple periods ofmodulation. Alternative, each amplitude modulation may differ accordingto the offset and/or scaling transformation of the stimulating signal136220.

FIG. 123C presents a non-limiting example of a third combination signal136250 of a therapeutic signal and a stimulating signal. In FIG. 123Cthe stimulating signal (136220 depicted in FIG. 122 ) may be used as aDC offset to the therapeutic signal (136210 depicted in FIG. 121 ). Itmay be recognized that the stimulating signal 136220 may also be alteredaccording to any offset or scaling transformation before being appliedas a DC offset to the therapeutic signal 136210. It may be recognizedthat a DC offset based on the stimulating signal 136220 may be appliedat any time to the therapeutic signal 136210 and may be applied multipletimes over the course of the application of the therapeutic signal136210. The DC offset applied to the therapeutic signal 136210 may bethe same over the course of multiple periods of offset application.Alternative, each DC offset to the therapeutic signal 136210 may differaccording to the offset and/or scaling transformation of the stimulatingsignal

It may be understood that the combination of a stimulating signal with atherapeutic signal is not limited to the examples disclosed above anddepicted in FIGS. 123A-123C. A stimulating signal may be combined with atherapeutic signal in the same manner throughout an electrosurgicalprocedure. Alternatively, a stimulating signal may be combined with atherapeutic signal in any of a number of different ways throughout theelectrosurgical procedure. In some aspects, a stimulating signal may becombined with a therapeutic signal based on a choice made by a healthcare professional during the electrosurgical procedure. For example, thesurgical probe may include one or more controls to permit the operatorof the electrosurgical device to choose a mode of combination of thestimulating signal with the therapeutic signal. The surgical probe mayalso include one or more controls to permit the operator of theelectrosurgical device to choose when the stimulating signal may beapplied. In some alternative aspects, the surgical probe may includecontrols to permit a user to vary one or more characteristics of thetherapeutic signal and/or the stimulating signal. Non-limiting examplesof such signal characteristics may include one or more frequencies, oneor more phases, and one or more amplitudes. In some alternative aspects,the control or controls of the stimulating signal and the therapeuticsignal, their respective characteristics, or their combination may belocated on the control unit of the electrosurgical device, or may beincorporated in a foot-operated controller.

In some aspects, a smart electrosurgical device may include a processor,memory components, and instructions resident in the memory componentsfor adjusting a therapeutic signal output based on a distance of theactive electrode from excitable tissues. In some aspects, suchprocessor, memory components, and instructions may form components ofthe controller. In some aspects, such processor, memory components, andinstructions may form components of the electrical generator. In someaspects, such processor, memory components, and instructions may formcomponents of a computer system separate from the smart electrosurgicaldevice.

FIG. 124 summarizes a one non-limiting method 136300 in which such acontrol may be effected. A controller may configure a generator tocombine 136310 a stimulating signal with a therapeutic signal to form anelectrode emitted signal. The controller may then cause an electrode totransmit 136320 the electrode emitted signal from an active electrodeinto a patient tissue. The controller may then receive 136330 a signalfrom a return signal pad in electrical communication with at least aportion of the patient. The signal returned by the return signal pad mayinclude a signal generated by any one or more sensing devices disposedwithin the return pad. The controller may analyze 136340 the returnsignal from the return signal pad. It may be recognized that theanalysis 136340 may include any one or more pre-processing methodsincluding, without limitation, noise filtering, signal extraction,baseline adjustment, or any other method that may permit the controllerto identify the return signal from the patient. Based on the returnsignal or any suitable manipulation of the return signal, the controllermay determine 136350 that an excitable tissue has been stimulated by theemitted electrode signal. When the controller has determined 136350 thatan excitable tissue has been stimulated by the emitted electrode signal,the controller may determine 136360 a distance of the excitable tissuefrom the active electrode. The controller may then adjust 136370 anamplitude of the therapeutic signal when the distance of the excitabletissue from the active electrode is less than a threshold value. In someaspects, the threshold value may be determined by a user of theelectrosurgical system. In some other aspects, the threshold value maybe based on a plurality of data acquired by the electrosurgical systemor a HUB system of which the electrosurgical system is a part. In someaspects, the threshold value may be based on one or more mathematicalmodels, physiological models (such as animal models), or on dataacquired during an electrosurgical procedure on the patient.

In some further aspects, a smart electrosurgical device may includeprocessor readable instructions within a memory component that, whenexecuted by a processor, may cause the processor associated with acontrol unit to combine a stimulating signal with a therapeutic signal.Such instructions may include, without limitation: determining the typeof stimulating signal (for example, amplitude, duration, and waveform);determining the type of signal combination (for example alternating,amplitude modulation, DC offset, or other type of combination);determining the timing of the signal combination (that is, when, duringa therapeutic activity, the therapeutic signal and the stimulatingsignals are combined, for example periodically, randomly, or at a singletime); or determining types of signal transformations of the stimulatingsignal before being combined with the therapeutic signal.

In some aspects, the smart electrosurgical device may include processorreadable instructions stored within a memory component that, whenexecuted by a processor, may cause the processor within the control unitto cause an active monopolar electrode to emit a therapeutic signal, acombined therapeutic signal and stimulating signal, or a stimulatingsignal upon contact with a patient's tissue. In some aspects, the smartelectrosurgical device may include processor readable instructionswithin a memory component that, when executed by a processor, may causethe processor within the control unit to combine a therapeutic signaland a stimulating signal, to form an electrode emitted signal and totransmit the emitted signal from the active electrode into a patienttissue. In some aspects, the smart electrosurgical device may includeprocessor readable instructions within a memory component that, whenexecuted by a processor, may cause the processor within the control unitto receive one or more return signals from the patient, the returnsignals comprising electrical current returned from the current emittedby the active monopolar electrode and received by a return signal pad.In some aspects, the smart electrosurgical device may include processorreadable instructions within a memory component that, when executed by aprocessor, may cause the processor within the control unit to receiveone or more output signals of the one or more sensing devices associatedwith a return pad in contact with the patient. In some aspects, thesmart electrosurgical device may include processor readable instructionswithin a memory component that, when executed by a processor, may causethe processor within the control unit to analyze the one or more outputsignals received from the one or more sensing devices associated with areturn pad in contact with the patient.

In some aspects, the smart electrosurgical device may include processorreadable instructions within a memory component that, when executed by aprocessor, may cause the processor within the control unit to determinethat an excitable tissue had been stimulated by the stimulating signal.In some examples, the one or more sensing devices may include anaccelerometer associated with the return pad. In one non-limitingexample, an output of an accelerometer may reflect to motion of a musclein contact therewith which is activated by the stimulating signal. Theamount of muscle motion may result at least in part from the amount ofstimulating current received by either the muscle tissue or a nerveenervating the muscle. Because tissue may act as a resistive element tothe propagation of the stimulating signal, the amount of muscleactivation may indicate a distance of the active electrode from eitherthe muscle or the enervating nerves.

In some aspects, the patient may rest in a supine position on the returnpad, and the sensor outputs of the return pad, such as one or moreaccelerometers, may indicate an amount of muscle motion of a patient'sback muscles in contact with the return pad. In an alternative aspect, areturn pad may be placed on a muscle or muscle group proximal to theposition of the surgical site wherein the electrosurgical device may beoperated. In some examples, the return pad may be place on a portion ofsuperficial abdominal muscles (such as the rectus abdominis muscles) foran abdominal surgery. In some examples, the return pad may be placed ona side portion of the abdomen to monitor stimulation of the externaloblique or the anterior serratus muscles.

In some aspects, the smart electrosurgical device may include processorreadable instructions within a memory component that, when executed by aprocessor, may cause the processor within the control unit to calculateor determine a distance of an excitable tissue from a distal end of theactive electrode based at least in part on a return signal or one ormore output signals from the one or more sensing devices associated witha return pad in contact with the patient. In some aspects, the smartelectrosurgical device may include processor readable instructionswithin a memory component that, when executed by a processor, may causethe processor within the control unit to adjust one or more of anamplitude, a frequency, and a phase of a therapeutic signal based atleast in part on a distance of an excitable tissue from the distal endof the active electrode. In some aspects, the amplitude, frequency,and/or phase of a therapeutic signal may be adjusted when the distanceof an excitable tissue from the active electrode is less than a firstpre-determined value. In some aspects, adjusting the amplitude,frequency, or phase of a therapeutic signal may result in theelectrosurgical systems emitting no therapeutic signal when the distanceof an excitable tissue from the active electrode is less than a secondpre-determined value.

In some additional aspects, the active electrode of a surgical probe ofthe electrosurgical device may be applied to a tissue solely todetermine a distance of excitable tissue from the active electrode. Insuch a use, the medical professional using the device may operate itsolely in a stimulating mode, without applying therapeutic signals tothe active electrode. In a stimulating mode, the user of the device mayoperate one or more controls configured to ramp a characteristic of thestimulating signal to determine under which conditions an excitabletissues is stimulated thereby. For example, a user may operate controlsconfigured to ramp a voltage or current amplitude of the stimulatingsignal from a low value to a high value. When a signal is received froma sensor (for example, an accelerometer sensing muscle movement), theelectrosurgical device may then calculate an approximate distance fromthe active electrode to the excitable tissue based at least in part onthe amplitude of the stimulating signal. In another example, a user mayoperate controls configured to ramp a frequency of the stimulatingsignal from a low value to a high value. When a signal is received froma sensor (for example, an accelerometer sensing muscle movement), theelectrosurgical device may then calculate an approximate distance fromthe active electrode to the excitable tissue based at least in part onthe frequency of the stimulating signal.

In some aspects, an electrosurgical device or a smart electrosurgicaldevice may be incorporated into a surgical HUB system. The HUB systemmay incorporate a number of hand-held medical devices, robotic medicaldevices, image acquisition devices, image display devices, communicationdevices, processing devices, networking devices, and other electronicdevices that may operate in a concerted and coordinated fashion. In someaspects, the HUB may include such devices located within a singlesurgical suite, located within a plurality of surgical suites, orlocated within any number of computer server locations. The computermemory modules, instructions, and processors disclosed above in thecontext of the control of a smart, stand-alone electrosurgical devicemay be distributed among any of the components of the surgical HUBsystem as may be appropriate.

In some aspects, additional information that may be acquired by thecomponents of the surgical HUB system may be used to improve theoperation of a smart electrosurgical device. For example, cameras andimaging systems directed at a surgical site may provide imaginginformation that can be used to determine the location of the distal endof the active electrode with respect to tissue in the surgical site. Theimage-based location of the distal end of the active electrode may beused with the return pad sensor output to refine the distance betweenthe active electrode and any excitable tissue in the patient. In somealternative examples, the HUB system may include data comprisinganatomical models related to the location of nerve and muscle tissue.Such model information may also be used along with the image-basedlocalization of the active electrode and the return pad sensor output tobetter determine the proximity of the active electrode to knownexcitable tissue.

Although the functions and devices disclosed above may be related solelyto an electrosurgical device, it may be recognized that such functionsand deices may also be incorporated into multi-mode surgical devicesthat include functions associated with an electrosurgical device. Forexample, a multi-mode surgical device may incorporate featuresassociated with an electrosurgical device along with features associatedwith an ultrasonic surgical device. In addition to the functionsdisclosed above regarding altering the properties of an electrosurgicaltherapeutic signal, a multi-mode device may include other functions. Forexample, a surgical device may use either RF energy or ultrasound for atherapeutic effect, for example cutting a tissue. In such a multi-modedevice, RF energy may be initially applied to a tissue for purposes ofcutting material, but the multi-mode device may be configured to switchto an ultrasound mode if the end effector of the multi-mode device isdetermined to be too close to excitable tissue.

Ultrasonic Surgical Instrument Architecture

FIG. 125 illustrates one aspect of an ultrasonic system 137010. Oneaspect of the ultrasonic system 137010 comprises an ultrasonic signalgenerator 137012 coupled to an ultrasonic transducer 137014, a handpiece assembly 137060 comprising a hand piece housing 137016, and anultrasonic blade 137050. The ultrasonic transducer 137014, which isknown as a “Langevin stack,” generally includes a transduction portion137018, a first resonator or end-bell 137020, and a second resonator orfore-bell 137022, and ancillary components. In various aspects, theultrasonic transducer 137014 is preferably an integral number ofone-half system wavelengths (nλ/2) in length as will be described inmore detail below. An acoustic assembly 137024 can include theultrasonic transducer 137014, a mount 137026, a velocity transformer137028, and a surface 137030.

It will be appreciated that the terms “proximal” and “distal” are usedherein with reference to a clinician gripping the hand piece assembly137060. Thus, the ultrasonic blade 137050 is distal with respect to themore proximal hand piece assembly 137060. It will be further appreciatedthat, for convenience and clarity, spatial terms such as “top” and“bottom” also are used herein with respect to the clinician gripping thehand piece assembly 137060. However, surgical instruments are used inmany orientations and positions, and these terms are not intended to belimiting and absolute.

The distal end of the end-bell 137020 is connected to the proximal endof the transduction portion 137018, and the proximal end of thefore-bell 137022 is connected to the distal end of the transductionportion 137018. The fore-bell 137022 and the end-bell 137020 have alength determined by a number of variables, including the thickness ofthe transduction portion 137018, the density and modulus of elasticityof the material used to manufacture the end-bell 137020 and thefore-bell 137022, and the resonant frequency of the ultrasonictransducer 137014. The fore-bell 137022 may be tapered inwardly from itsproximal end to its distal end to amplify the ultrasonic vibrationamplitude of the velocity transformer 137028, or, alternately, fore-bell137022 may have no amplification.

Referring again to FIG. 125 , end-bell 137020 can include a threadedmember extending therefrom which can be configured to be threadablyengaged with a threaded aperture in fore-bell 137022. In variousaspects, piezoelectric elements, such as piezoelectric elements 137032,for example, can be compressed between end-bell 137020 and fore-bell137022 when end-bell 137020 and fore-bell 137022 are assembled together.Piezoelectric elements 137032 may be fabricated from any suitablematerial, such as, for example, lead zirconate-titanate, leadmeta-niobate, lead titanate, and/or any suitable piezoelectric crystalmaterial, for example.

In various aspects, as discussed in greater detail below, transducer137014 can further comprise electrodes, such as positive electrodes137034 and negative electrodes 137036, for example, which can beconfigured to create a voltage potential across one or morepiezoelectric elements 137032. Each of the positive electrodes 137034,negative electrodes 137036, and the piezoelectric elements 137032 cancomprise a bore extending through the center which can be configured toreceive the threaded member of end-bell 137020. In various aspects, thepositive and negative electrodes 137034 and 137036 are electricallycoupled to wires 137038 and 137040, respectively, wherein the wires137038 and 137040 can be encased within a cable 137042 and electricallyconnectable to the ultrasonic signal generator 137012 of the ultrasonicsystem 137010.

In various aspects, the ultrasonic transducer 137014 of the acousticassembly 137024 converts the electrical signal from the ultrasonicsignal generator 137012 into mechanical energy that results in primarilylongitudinal vibratory motion of the ultrasonic transducer 137014 andthe ultrasonic blade 137050 at ultrasonic frequencies. An ultrasonicsurgical generator 137012 can include, for example, the generator 1100(FIG. 18 ) or the generator 137012 (FIG. 125 ). When the acousticassembly 137024 is energized, a vibratory motion standing wave isgenerated through the acoustic assembly 137024. A suitable vibrationalfrequency range may be about 20 Hz to 120 kHz and a well-suitedvibrational frequency range may be about 30-70 kHz and one exampleoperational vibrational frequency may be approximately 55.5 k Hz.

The amplitude of the vibratory motion at any point along the acousticassembly 137024 may depend upon the location along the acoustic assembly137024 at which the vibratory motion is measured. A minimum or zerocrossing in the vibratory motion standing wave is generally referred toas a node (i.e., where motion is usually minimal), and an absolute valuemaximum or peak in the standing wave is generally referred to as ananti-node (i.e., where motion is usually maximal). The distance betweenan anti-node and its nearest node is one-quarter wavelength (λ/4).

As outlined above, the wires 137038, 137040 transmit an electricalsignal from the ultrasonic signal generator 137012 to the positiveelectrodes 137034 and the negative electrodes 137036. The piezoelectricelements 137032 are energized by the electrical signal supplied from theultrasonic signal generator 137012 in response to a foot switch 137044,for example, to produce an acoustic standing wave in the acousticassembly 137024. The electrical signal causes disturbances in thepiezoelectric elements 137032 in the form of repeated smalldisplacements resulting in large compression forces within the material.The repeated small displacements cause the piezoelectric elements 137032to expand and contract in a continuous manner along the axis of thevoltage gradient, producing longitudinal waves of ultrasonic energy.

In various aspects, the ultrasonic energy produced by transducer 137014can be transmitted through the acoustic assembly 137024 to theultrasonic blade 137050 via an ultrasonic transmission waveguide 137046.In order for the acoustic assembly 137024 to deliver energy to theultrasonic blade 137050, the components of the acoustic assembly 137024are acoustically coupled to the ultrasonic blade 137050. For example,the distal end of the ultrasonic transducer 137014 may be acousticallycoupled at the surface 137030 to the proximal end of the ultrasonictransmission waveguide 137046 by a threaded connection such as a stud137048.

The components of the acoustic assembly 137024 can be acoustically tunedsuch that the length of any assembly is an integral number of one-halfwavelengths (nλ/2), where the wavelength λ is the wavelength of apre-selected or operating longitudinal vibration drive frequency fd ofthe acoustic assembly 137024, and where n is any positive integer. It isalso contemplated that the acoustic assembly 137024 may incorporate anysuitable arrangement of acoustic elements.

The ultrasonic blade 137050 may have a length substantially equal to anintegral multiple of one-half system wavelengths (λ/2). A distal end137052 of the ultrasonic blade 137050 may be disposed at, or at leastnear, an antinode in order to provide the maximum, or at least nearlymaximum, longitudinal excursion of the distal end. When the transducerassembly is energized, in various aspects, the distal end 137052 of theultrasonic blade 137050 may be configured to move in the range of, forexample, approximately 10 to 500 microns peak-to-peak and preferably inthe range of approximately 30 to 150 microns at a predeterminedvibrational frequency.

As outlined above, the ultrasonic blade 137050 may be coupled to theultrasonic transmission waveguide 137046. In various aspects, theultrasonic blade 137050 and the ultrasonic transmission guide 137046 asillustrated are formed as a single unit construction from a materialsuitable for transmission of ultrasonic energy such as, for example,Ti6Al4V (an alloy of titanium including aluminum and vanadium),aluminum, stainless steel, and/or any other suitable material.Alternately, the ultrasonic blade 137050 may be separable (and ofdiffering composition) from the ultrasonic transmission waveguide137046, and coupled by, for example, a stud, weld, glue, quick connect,or other suitable known methods. The ultrasonic transmission waveguide137046 may have a length substantially equal to an integral number ofone-half system wavelengths (λ/2), for example. The ultrasonictransmission waveguide 137046 may be preferably fabricated from a solidcore shaft constructed out of material that propagates ultrasonic energyefficiently, such as titanium alloy (i.e., Ti6A14V) or an aluminumalloy, for example.

In the aspect illustrated in FIG. 125 , the ultrasonic transmissionwaveguide 137046 comprises a plurality of stabilizing silicone rings orcompliant supports 137056 positioned at, or at least near, a pluralityof nodes. The silicone rings 137056 can dampen undesirable vibration andisolate the ultrasonic energy from a sheath 137058 at least partiallysurrounding waveguide 137046, thereby assuring the flow of ultrasonicenergy in a longitudinal direction to the distal end 137052 of theultrasonic blade 137050 with maximum efficiency.

As shown in FIG. 125 , the sheath 137058 can be coupled to the distalend of the handpiece assembly 137060. The sheath 137058 generallyincludes an adapter or nose cone 137062 and an elongated tubular member137064. The tubular member 137064 is attached to and/or extends from theadapter 137062 and has an opening extending longitudinally therethrough.In various aspects, the sheath 137058 may be threaded or snapped ontothe distal end of the housing 137016. In at least one aspect, theultrasonic transmission waveguide 137046 extends through the opening ofthe tubular member 137064 and the silicone rings 137056 can contact thesidewalls of the opening and isolate the ultrasonic transmissionwaveguide 137046 therein. In various aspects, the adapter 137062 of thesheath 137058 is preferably constructed from Ultem®, for example, andthe tubular member 137064 is fabricated from stainless steel, forexample. In at least one aspect, the ultrasonic transmission waveguide137046 may have polymeric material, for example, surrounding it in orderto isolate it from outside contact.

As described above, a voltage, or power source can be operably coupledwith one or more of the piezoelectric elements of a transducer, whereina voltage potential applied to each of the piezoelectric elements cancause the piezoelectric elements to expand and contract, or vibrate, ina longitudinal direction. As also described above, the voltage potentialcan be cyclical and, in various aspects, the voltage potential can becycled at a frequency which is the same as, or nearly the same as, theresonant frequency of the system of components comprising transducer137014, waveguide 137046, and ultrasonic blade 137050, for example. Invarious aspects, however, certain of the piezoelectric elements withinthe transducer may contribute more to the standing wave of longitudinalvibrations than other piezoelectric elements within the transducer. Moreparticularly, a longitudinal strain profile may develop within atransducer wherein the strain profile may control, or limit, thelongitudinal displacements that some of the piezoelectric elements cancontribute to the standing wave of vibrations, especially when thesystem is being vibrated at or near its resonant frequency.

The piezoelectric elements 137032 are configured into a “Langevinstack,” in which the piezoelectric elements 137032 and their activatingelectrodes 137034 and 137036 (together, transducer 137014) areinterleaved. The mechanical vibrations of the activated piezoelectricelements 137032 propagate along the longitudinal axis of the transducer137014, and are coupled via the acoustic assembly 137024 to the end ofthe waveguide 137046. Such a mode of operation of a piezoelectricelement is frequently described as the D33 mode of the element,especially for ceramic piezoelectric elements comprising, for example,lead zirconate-titanate, lead meta-niobate, or lead titanate. The D33mode of a ceramic piezoelectric element is illustrated in FIGS.126A-126C.

FIG. 126A depicts a piezoelectric element 137200 fabricated from aceramic piezoelectric material. A piezoelectric ceramic material is apolycrystalline material comprising a plurality of individualmicrocrystalline domains. Each microcrystalline domain possesses apolarization axis along which the domain may expand or contract inresponse to an imposed electric field. However, in a native ceramic, thepolarization axes of the microcrystalline domains are arranged randomly,so there is no net piezoelectric effect in the bulk ceramic. A netre-orientation of the polarization axes may be induced by subjecting theceramic to a temperature above the Curie temperature of the material andplacing the material in a strong electrical field. Once the temperatureof the sample is dropped below the Curie temperature, a majority of theindividual polarization axes will be re-oriented and fixed in a bulkpolarization direction. FIG. 126A illustrates such a piezoelectricelement 137200 after being polarized along the inducing electric fieldaxis P. While the un-polarized piezoelectric element 137200 lacks anynet piezoelectric axis, the polarized element 137200 can be described aspossessing a polarization axis, d3, parallel to the inducing field axisP direction. For completeness, an axis orthogonal to the d3 axis may betermed a d1 axis. The dimensions of the piezoelectric element 137200 arelabeled as length (L), width (W), and thickness (T).

FIGS. 126B and 126C illustrate the mechanical deformations of apiezoelectric element 137200 that may be induced by subjecting thepiezoelectric element 137200 to an actuating electrical field E orientedalong the d3 (or P) axis. FIG. 126B illustrates the effect of anelectric field E having the same direction as the polarization field Palong the d3 axis on a piezoelectric element 137205. As illustrated inFIG. 126B, the piezoelectric element 137205 may deform by expandingalong the d3 axis while compressing along the d1 axis. FIG. 126Cillustrates the effect of an electric field E having the opposingdirection to the polarization field P along the d3 axis on apiezoelectric element 137210. As illustrated in FIG. 126C, thepiezoelectric element 137210 may deform by compressing along the d3axis, while expanding along the d1 axis. Vibrational coupling along thed3 axis during the application of an electric field along the d3 axismay be termed D33 coupling or activation using a D33 mode of apiezoelectric element. The transducer 137014 illustrated in FIG. 125 canuse the D33 mode of the piezoelectric elements 137032 for transmittingmechanical vibrations along the waveguide 46 to the ultrasonic blade137050. Because the piezoelectric element also deforms along the d1axis, vibrational coupling along the d1 axis during the application ofan electric field along the d3 axis may also be an effective source ofmechanical vibrations. Such coupling may be termed D31 coupling oractivation using a D31 mode of a piezoelectric element.

As illustrated by FIGS. 126A-126C, during operation in the D31 mode,transverse expansion of piezoelectric elements 137200, 137205, 137210may be mathematically modeled by the following equation:

$\frac{\Delta L}{L} = {\frac{\Delta W}{W} = \frac{V_{d31}}{T}}$

In the equation, L, W, and T refer to the length, width and thicknessdimensions of a piezoelectric element, respectively. V_(d31) denotes thevoltage applied to a piezoelectric element operating in the D31 mode.The quantity of transverse expansion resulting from the D31 couplingdescribed above is represented by ΔL (i.e., expansion of thepiezoelectric element along the length dimension) and ΔW (i.e.,expansion of the piezoelectric element along the width dimension).Additionally, the transverse expansion equation models the relationshipbetween ΔL and ΔW and the applied voltage V_(d31). Disclosed below areaspects of ultrasonic surgical instruments based on D31 activation by apiezoelectric element.

In various aspects, as described below, an ultrasonic surgicalinstrument can comprise a transducer configured to produce longitudinalvibrations, and a surgical instrument having a transducer base plate(e.g., a transducer mounting portion) operably coupled to thetransducer, an end effector, and waveguide therebetween. In certainaspects, as also described below, the transducer can produce vibrationswhich can be transmitted to the end effector, wherein the vibrations candrive the transducer base plate, the waveguide, the end effector, and/orthe other various components of the ultrasonic surgical instrument at,or near, a resonant frequency. In resonance, a longitudinal strainpattern, or longitudinal stress pattern, can develop within thetransducer, the waveguide, and/or the end effector, for example. Invarious aspects, such a longitudinal strain pattern, or longitudinalstress pattern, can cause the longitudinal strain, or longitudinalstress, to vary along the length of the transducer base plate,waveguide, and/or end effector, in a sinusoidal, or at leastsubstantially sinusoidal, manner. In at least one aspect, for example,the longitudinal strain pattern can have maximum peaks and zero points,wherein the strain values can vary in a non-linear manner between suchpeaks and zero points.

FIG. 127 illustrates an ultrasonic surgical instrument 137250 thatincludes an ultrasonic waveguide 137252 attached to an ultrasonictransducer 137264 by a bonding material, where the ultrasonic surgicalinstrument 137250 is configured to operate in a D31 mode, according toone aspect of this disclosure. The ultrasonic transducer 137264 includesfirst and second piezoelectric elements 137254 a, 137254 b attached tothe ultrasonic waveguide 137252 by a bonding material. The piezoelectricelements 137254 a, 137254 b include electrically conductive plates137256 a, 137256 b to electrically couple one pole of a voltage sourcesuitable to drive the piezoelectric elements 137254 a, 137254 b (e.g.,usually a high voltage). The opposite pole of the voltage source iselectrically coupled to the ultrasonic waveguide 137252 by electricallyconductive joints 137258 a, 137258 b. In one aspect, the electricallyconductive plates 137256 a, 137256 b are coupled to a positive pole ofthe voltage source and the electrically conductive joints 137258 a,137258 b are electrically coupled to ground potential through the metalultrasonic waveguide 137252. In one aspect, the ultrasonic waveguide137252 is made of titanium or titanium alloy (i.e., Ti6A14V) and thepiezoelectric elements 137254 a, 137254 b are made of PZT. The polingaxis (P) of the piezoelectric elements 137254 a, 137254 b is indicatedby the direction arrow 137260. The motion axis of the ultrasonicwaveguide 137252 in response to excitation of the piezoelectric elements137254 a, 137245 b is shown by a motion arrow 137262 at the distal endof the ultrasonic waveguide 137252 generally referred to as theultrasonic blade portion of the ultrasonic waveguide 137252. The motionaxis 137262 is orthogonal to the poling axis (P) 137260.

In conventional D33 ultrasonic transducer architectures as shown in FIG.125 , the bolted piezoelectric elements 137032 utilize electrodes137034, 137036 to create electrical contact to both sizes of eachpiezoelectric element 137033. The D31 architecture 137250 according toone aspect of this disclosure, however, employs a different technique tocreate electrical contact to both sides of each piezoelectric element137254 a, 137254 b. Various techniques for providing electrical contactto the piezoelectric elements 137254 a, 137254 b include bondingelectrical conductive elements (e.g., wires) to the free surface of eachpiezoelectric element 137254 a, 137254 b for the high potentialconnection and bonding each piezoelectric element 137254 a, 137254 b theto the ultrasonic waveguide 137252 for the ground connection usingsolder, conductive epoxy, or other techniques described herein.Compression can be used to maintain electrical contact to the acoustictrain without making a permanent connection. This can cause an increasein device thickness and should be controlled to avoid damaging thepiezoelectric elements 137254 a, 137254 b. Low compression can damagethe piezoelectric element 137254 a, 137254 b by a spark gap and highcompression can damage the piezoelectric elements 137254 a, 137254 b bylocal mechanical wear. In other techniques, metallic spring contacts maybe employed to create electrical contact with the piezoelectric elements137254 a, 137254 b. Other techniques may include foil-over-foam gaskets,conductive foam, and solder. In some aspects, there is an electricalconnection to both sides of the piezoelectric elements 137254 a, 137254b in the D31 acoustic train configuration. The electrical groundconnection can be made to the metal ultrasonic waveguide 137252, whichis electrically conductive, if there is electrical contact between thepiezoelectric elements 137254 a, 137254 b and the ultrasonic waveguide137252.

In conventional D33 ultrasonic transducer architectures as shown in FIG.125 , a bolt provides compression that acoustically couples thepiezoelectric elements rings to the ultrasonic waveguide. The D31architecture 137250 according to one aspect of this disclosure employs avariety of different techniques to acoustically couple the piezoelectricelements 137254 a, 137254 b to the ultrasonic waveguide 137252. Someillustrative techniques are disclosed in U.S. patent application Ser.No. 15/679,940, titled ULTRASONIC TRANSDUCER TECHNIQUES FOR ULTRASONICSURGICAL INSTRUMENT, filed Aug. 17, 2017, which is hereby incorporatedby reference in its entirety.

FIGS. 128 and 129 illustrate various views of an ultrasonic surgicalinstrument 137400. In various aspects, the surgical instrument 137400can be embodied generally as a pair of ultrasonic shears, as shown. Inaspects where the ultrasonic surgical instrument 137400 is embodied as apair of ultrasonic shears, the surgical instrument 137400 can include afirst arm 137412 a pivotably connected to a second arm 137412 b at apivot point 137413 (e.g., by a fastener). The first arm 137412 aincludes a clamp arm 137416 positioned at its distal end that includes acooperating surface (e.g., a pad) that is configured to cooperate withan ultrasonic blade 137415 extending distally from the second arm 137412b. The clamp arm 137416 and the ultrasonic blade 137415 can collectivelydefine an end effector 137410. Actuating the first arm 137412 a in afirst direction causes the clamp arm 137416 to pivot towards theultrasonic blade 137415 and actuating the first arm 137412 a in a seconddirection causes the clamp arm 137416 to pivot away from the ultrasonicblade 137415. In some aspects, the clamp arm 13716 further includes apad constructed from a polymeric or other compliant material and engagesthe ultrasonic blade 137415. The surgical instrument 137400 furtherincludes a transducer assembly, such as is described above with respectto FIGS. 125-127 . The transducer assembly can be arranged in, e.g., aD31 or D33 architecture. The surgical instrument 137400 furthercomprises a housing 137414 enclosing various components of an ultrasonicsystem 137010 (FIG. 125 ), including first and second piezoelectricelements 137419 a, 137419 b of an ultrasonic transducer 137418 arrangedin a D31 architecture, a transducer base plate 137428 (e.g., atransducer mounting portion) comprising flat faces on opposite sides toreceive the piezoelectric elements 137419 a, 137419 b, and a waveguide137417 that longitudinally translates vibrations from the ultrasonictransducer 137418 to the ultrasonic blade 137415. Further, the surgicalinstrument 137400 is connectable to an ultrasonic signal generator fordriving the ultrasonic transducer 137418, as described above. Thewaveguide 137417 can comprise a plurality of stabilizing silicone ringsor compliant supports 137411 positioned at, or at least near, aplurality of nodes (i.e., points located at a minimum or zero crossingin the vibratory motion standing wave). The compliant supports areconfigured to dampen undesirable lateral vibration in order to ensurethat ultrasonic energy is transmitted longitudinally to the ultrasonicblade 137415. The waveguide 137417 extends through the housing 137414and the second arm 137412 b and terminates at the ultrasonic blade137415, externally to the housing 137414. The ultrasonic blade 137415and the clamp arm 137416 are cooperating elements that are configured tograsp tissue, allowing the end effector 137410 to clamp andcut/coagulate tissue. Moving the clamp arm 137416 towards the ultrasonicblade 137415 causes tissue situated therebetween to contact theultrasonic blade 137415, allowing the ultrasonic blade 137415 to operateagainst the grasped tissue. As the ultrasonic blade 137415ultrasonically vibrates against the gasped tissue, the ultrasonic blade137415 generates frictional forces that cause the tissue to coagulateand eventually sever along the cutting length of the ultrasonic blade137415.

The cutting length of the surgical instrument 137400 corresponds to thelengths of the ultrasonic blade 137415 and the cooperating surface ofthe clamp arm 137416. Tissue that is held between the ultrasonic blade137415 and the cooperating surface of the clamp arm 137416 for asufficient period of time is cut by the ultrasonic blade 137415, asdescribed above. The ultrasonic blade 137415 and the correspondingportion of the clamp arm 137416 can have a variety of shapes. In variousaspects, the ultrasonic blade 137415 and/or clamp arm 137416 can besubstantially linear in shape or have a curvature. In some aspects, theportion of the clamp arm 137416 configured to bring tissue into contactwith the ultrasonic blade 137415 can correspond to the shape of theultrasonic blade 137415 so that the clamp arm 137416 is alignedtherewith.

Various additional details regarding ultrasonic transducer assembliesand ultrasonic shears can be found in U.S. patent application Ser. No.15/679,940, titled ULTRASONIC TRANSDUCER TECHNIQUES FOR ULTRASONICSURGICAL INSTRUMENT, filed Aug. 17, 2017, which is hereby incorporatedby reference in its entirety.

Advanced Energy Device Activation Options

FIG. 130 illustrates a block diagram of a surgical system 137500, inaccordance with at least one aspect of the present disclosure. Thesurgical system 137500 can include, for example, the surgical system1000 depicted in FIG. 22 and/or the ultrasonic surgical instrumentsystem 137010 depicted in FIG. 125 . The surgical system 137500 caninclude a surgical instrument 137400, such as the ultrasonic surgicalinstrument 1104 (FIG. 22 ), that is electrically connectable to anelectrosurgical generator 137504, such as generator 1100 (FIGS. 22, 24 )or the generator 137012 (FIG. 125 ), capable of producing ultrasonicenergy, monopolar or bipolar radiofrequency (RF) energy, other types ofenergy, and/or combinations thereof for driving the surgical instrument137400.

In the aspect depicted in FIG. 130 , the surgical instrument 137400includes a transducer assembly 137510 that comprises at least twopiezoelectric elements. The transducer assembly 137510 is operablycoupled to the ultrasonic blade 137512 such that the transducer assembly137510 can ultrasonically oscillate the ultrasonic blade 137512 whenthen transducer assembly 137510 is activated, as is described inconnection with FIGS. 125-127 . The transducer assembly 137510 is inturn electrically coupled to the generator 137504 to receive energytherefrom. Accordingly, when energized by the generator 137504, thetransducer assembly 137510 is configured to ultrasonically oscillate theultrasonic blade 137512 in order to sever and/or coagulate tissuecaptured by the surgical instrument 137400.

In another aspect, the surgical instrument 137400 includes one or moreelectrodes 796 (FIG. 19 ) or other conducting elements located at theend effector 792 (FIG. 19 ). The electrodes 796 are in turn electricallycoupled to the generator 137504 to receive energy therefrom. Whenenergized by the generator 137504, the electrodes 796 are configured toapply RF energy in order to sever and/or coagulate tissue captured bythe surgical instrument 137400, as is described in connection with FIG.17 .

The surgical instrument 137400 further includes a control circuit 137506that is communicably coupled to a sensor 137508 and communicablycouplable to the generator 137504. The control circuit 137506 caninclude, for example, a processor coupled to primary and/or secondarycomputer memory for executing instructions stored on the memory, amicrocontroller, an application-specific integrated circuit (ASIC), afield-programmable gate array (FPGA), and other such devices. The sensor137508 is configured to sense a property of the environment and/or thesurgical instrument 137400 and provide an output corresponding to thepresence or magnitude of the sensed property. The control circuit 137506is in turn configured to selectively control the activation of thetransducer assembly 137510 and/or electrodes 796 according to whetherthe sensed property is above, below, or at a threshold value. In otherwords, the control circuit 137506 is configured to control theactivation of the transducer assembly 137510 and/or electrodes 796according to the sensor output relative to a threshold. In one aspect,the threshold can be stored in a memory of the surgical instrument137400 and retrieved by the control circuit 137506 to compare the outputsignal from the sensor 137508 thereagainst.

In various other exemplifications, the control circuit 137506 and/orsensor 137508 may be external to the surgical instrument 137400. Inthese exemplifications, the control circuit 137506 and/or sensor 137508can be communicably coupled to each other and/or the generator 137504via any wired communication protocol (e.g., I²C) or wirelesscommunication protocol (e.g., Bluetooth) and include the appropriatehardware and/or software to effectuate the particular communicationprotocol. In still other exemplifications, the generator 137504 can beintegral, internal, or otherwise incorporated with the surgicalinstrument 137400, rather than being external thereto, as depicted inFIG. 18 and FIG. 125 .

FIGS. 131-132C illustrate various views of a surgical instrument 137400including a sensor assembly 137508 configured to detect a magneticreference 137404, in accordance with at least one aspect of the presentdisclosure. In the following description of FIGS. 131-132C, referenceshould also be made to FIG. 130 . In one aspect, the sensor assembly137508 includes a sensor 137402 that is configured to detect theposition or state (e.g., opened or closed) of the surgical instrument137400 by detecting the corresponding position or location of a magneticreference 137404. The sensor 137402 can include, for example, a Halleffect sensor that is configured to detect the location of the magneticreference 137404 relative thereto. Accordingly, the magnetic reference137404 is configured such that its position corresponds to the positionand/or state of the surgical instrument 137400. The Hall effect sensorcan include, for example, a Hall element configured to detect therelative distance between the magnetic reference 137404 and the sensor137402 or an assembly of multiple Hall elements configured to detect themultidimensional position or orientation of the magnetic reference137404 relative to the sensor 137402 (e.g., a TLV493D-A1B6 3D magneticsensor from Infineon Technologies). Further, the Hall effect sensor caninclude linear Hall effect sensors (i.e., Hall effect sensors where theoutput varies linearly with the magnetic flux density) or threshold Halleffect sensors (i.e., Hall effect sensors where the output drops sharplyaccording to decreasing magnetic flux density).

In the aspect depicted in FIG. 131 , the magnetic reference 137404includes a wearable magnet 137406. Accordingly, the sensor 137402 isconfigured to detect the relative position of the wearable magnet 137406as worn, for example, on the hand of a surgeon. In various aspects, therelative position of the wearable magnet 137406 with respect to thesensor 137402 can include, for example, the relative distance betweenthe wearable magnet 137406 and the sensor 137402 and/or the relativeorientation of the wearable magnet 137406 with respect to the sensor137402. In one example, the wearable magnet 137406 can be incorporatedwith or positioned in or on a ring that is worn on a finger of thesurgeon (e.g., over a surgical glove). In another example, the wearablemagnet 137406 can be attached or integral to a surgical glove wearableby the surgeon. In these aspects, as the wearable magnet 137406 islocated on the surgeon's hand and the surgeon's hand grips the arm137412 of the surgical instrument 137400 during use thereof, theposition of the wearable magnet 137406 as detected by the sensor 137402corresponds to the relative position of the arm 137412 of the surgicalinstrument 137400. By sensing the relative position of the arm 137412 ofthe surgical instrument 137400, the control circuit 137506 can therebydetermine whether the surgical instrument 137400 is opened, closed, orin an intermediate position therebetween.

In another exemplification, the positions of the wearable magnet 137406and the sensor 137402 can be reversed from the aspect described above.In other words, the magnet can be positioned on or in the surgicalinstrument 137400 and the sensor 137402 can be positioned on or worn bythe surgeon (e.g., incorporated into a ring or a surgical glove, asdescribed above). Otherwise, this exemplification functions in a similarmanner to the exemplification that is described above.

In the aspect depicted in FIGS. 132A-C, the magnetic reference 137404includes an integral magnet 137408 positioned in or on a movablecomponent of the surgical instrument 137400, such as the arm 137412thereof. Accordingly, the sensor 137402 is configured to detect therelative position of the integral magnet 137408 within the arm 137412 ofthe surgical instrument 137400. The integral magnet 137408 and thesensor 137402 can each be positioned such that opening and closing thesurgical instrument 137400 causes the integral magnet 137408 to moverelative to the sensor 137402. In the depicted aspect, the integralmagnet 137408 can be positioned on or in the movable arm 137412 of thesurgical instrument 137400 and the sensor 137402 can be positioned on orin the housing 137414 of the surgical instrument 137400. In theseaspects, the position of the integral magnet 137408 detected by thesensor 137402 corresponds to the relative position of the arm 137412 ofthe surgical instrument 137400. By sensing the relative position of thearm 137412 of the surgical instrument 137400, the control circuit 137506can thereby determine whether the surgical instrument 137400 is opened,closed, or in an intermediate position therebetween.

In another exemplification, the positions of the integral magnet 137408and the sensor 137402 can be reversed from the aspect described above.In other words, the integral magnet 137408 can be positioned on or inthe housing 137414 of the surgical instrument 137400 and the sensor137402 can be positioned on or in the corresponding movable component(e.g., the arm 137412) of the surgical instrument 137400 that is beingtracked. Otherwise, this exemplification functions in a similar mannerto the exemplification that is described above.

The sensor 137402 is configured to produce an output that corresponds tothe position of the magnetic reference 137404 relative thereto (e.g.,the distance between the magnetic reference 137404 and the sensor 137402and/or the orientation of the magnetic reference 137404 with respect tothe sensor 137402). Thus, as the magnetic reference 137404 and/or thesensor 137402 move with respect to each other as the surgical instrument137400 is closed, opened, or otherwise manipulated by a surgeon, thesensor 137400 is able to detect the relative position of the magneticreference 137404 according to the sensed magnetic field of the magneticreference 137404. The sensor 137402 can then produce an outputcorresponding to the sensed magnetic field of the magnetic reference137404. In one aspect where the sensor 137402 includes a Hall effectsensor, the sensor output can be a voltage, wherein the magnitude of theoutput voltage corresponds to the strength of the magnetic field fromthe magnetic reference 137404 sensed by the sensor 137402.

In one aspect, the control circuit 137506 is configured to receive theoutput from the sensor 137402 and then compare the output of the sensor137402 to a threshold. The control circuit 137506 can further activateor deactivate the surgical instrument 137400 according the comparisonbetween the output of the sensor 137402 and the threshold. The thresholdcan be, e.g., predetermined or set by a user of the surgical instrument137400. The output of the sensor 137402 can correspond to the positionof the arm of the surgical instrument 137400 (either directly, as in theaspect depicted in FIGS. 132A-C, or indirectly, as in the aspectdepicted in FIG. 131 ), which in turn controls the position of the clamparm 137416 (FIG. 128 ) relative to the ultrasonic blade 137512.Therefore, the output of the sensor 137402 corresponds to the positionof the clamp arm 137416 of the surgical instrument 137402 between, e.g.,an open position and a closed position. Further in theseexemplifications, the threshold can correspond to a threshold distancebetween the magnetic reference 137404 and the sensor 137402. FIG. 132B,for example, can represent an open position for the surgical instrument137400 (i.e., the integral magnet 137408 is not within a thresholddistance to the sensor 137402) and FIG. 132C, for example, can representa closed position of the surgical instrument 137400 (i.e., the integralmagnet 137408 is within a threshold distance to the sensor 137402).

In one example, the control circuit 137506 can determine whether themagnetic reference 137404 is positioned less than or equal to athreshold distance from the sensor 137402. In this example, if thecontrol circuit 137506 determines that the sensor output exceeds thethreshold, then the control circuit 137506 can activate the surgicalinstrument 137400. In another example, the control circuit 137506 candetermine whether the magnetic reference 137404 is positioned greaterthan or equal to a threshold distance from the sensor 137402. In thisexample, if the control circuit 137506 determines that the voltageoutput of the sensor 137402 is less than or equal to the threshold, thenthe control circuit 137506 can activate the surgical instrument 137400.The control circuit 137506 can activate the surgical 137400 bytransmitting a signal to the generator 137504 that cause the generator137504 to energize the transducer assembly 137510 and/or RF electrodes796 to cut and/or coagulate tissue captured by the surgical instrument137400. In sum, in some aspects the control circuit 137506 can beconfigured to determine whether the surgical instrument 137400 issufficiently closed and, if it is, then activate the surgical instrument137400.

In other aspects, the control circuit 137506 can be configured takeother actions if it determines that the surgical instrument 137400 issufficiently closed, such as providing a prompt to the user ortransmitting data to a surgical hub 106, as described in connection withFIGS. 1-11 . In still other aspects, the control circuit 137506 can beconfigured to determine whether the surgical instrument 137400 issufficiently opened or at some particular position (or range ofpositions) between the opened and closed positions. If the surgicalinstrument 137400 is at or within the defined position(s), the controlcircuit 137506 can accordingly activate the surgical instrument 137400,deactivate the surgical instrument 137400, or take a variety of otheractions.

In some aspects, the control circuit 137506 can be configured to detecttapping, rubbing, and other types of motions based upon the amplitude,frequency, and/or direction of the motion of the magnetic reference137404 detected via the sensor 137402. Such motions can be detectedbecause the change in the strength of the magnetic field over timedetected by the sensor 137402 can be characterized (empirically orotherwise) and defined for different types of motions. For example, atapping motion could be detectable according to the frequency in thechange of the magnetic field detected by the sensor 137402 in adirection substantially perpendicular to the longitudinal axis of thesurgical instrument 137400. As another example, a rubbing motion couldbe detectable according to the frequency in the change of the magneticfield detected by the sensor 137402 in a direction substantiallyparallel to the longitudinal axis of the surgical instrument 137400. Insome aspects, the control circuit 137506 can be configured to change thestate, mode, and/or properties of the surgical instrument 137400according to the detected motions. For example, the control circuit137506 could be configured to activate the surgical instrument 137400upon detecting a tapping motion via the sensor 137402.

FIGS. 133A-B illustrates perspective views of a surgical instrument137400 including a sensor assembly 137508 configured to detect contactthereagainst and FIG. 134 illustrates a corresponding circuit diagram,in accordance with at least one aspect of the present disclosure. In thefollowing description of FIGS. 133A-134 , reference should also be madeto FIG. 130 . In one aspect, the sensor assembly 137508 can include atouch sensor 137420 that is configured to detect force, contact, and/orpressure thereagainst. The touch sensor 137420 can comprise, e.g., aforce-sensitive resistor (FSR) 137421. In one exemplification depictedin FIG. 133A, the touch sensor 137420 is oriented transverse to thelongitudinal axis of the surgical instrument 137400. In thisexemplification, the touch sensor 137420 defines a surface extendingorthogonally from the housing 137414 relative to the longitudinal axisof the surgical instrument 137400. In another exemplification depictedin FIG. 133B, the touch sensor 137420 extends along the lateralsurface(s) of the housing 137414. In this exemplification, the touchsensor 137420 can be integral to or positioned in or on the housing137414 of the surgical instrument 137400. In either of theseexemplifications, the touch sensor 137420 can be utilized by a surgeonto, e.g., activate the transducer assembly 137510 of the surgicalinstrument 137400 or otherwise provide input to the surgical instrument137400 (e.g., in order to control one or more functions of the surgicalinstrument 137400).

In one aspect where the touch sensor 137420 includes a FSR 137421, asdepicted in FIG. 134 , the surgical instrument 137400 can include acircuit to control the activation of the electrosurgical generator137426 electrically connectable to the surgical instrument 137400. Inthis exemplification, the FSR 137421 is electrically coupled to ananalog-to-digital converter (ADC) 137422 and a control circuit 137424(e.g., a microcontroller or an ASIC). As a force F is applied to the FSR137421, the voltage output of the FSR 137721 varies accordingly. The ADC137422 then converts the analog signal from the FSR 137421 to a digitalsignal, which is then supplied to the control circuit 137424. In oneexemplification, the control circuit 137424 can then compare thereceived signal (which is indicative of the output voltage of the FSR137421, which in turn is indicative of the force F or pressureexperienced by the FSR 137421) to a threshold to determine whether toactivate the electrosurgical generator 137426. In one exemplification,if the received signal does exceed the threshold, the control circuit137424 can transmit a signal to the electrosurgical generator 137426 toactivate it and energize the transducer assembly 137510 and/or RFelectrodes 796 to cut and/or coagulate tissue captured by the surgicalinstrument 137400. In another exemplification, the control circuit137424 can transmit the output of the FSR 137421 or a signal indicativethereof to a control circuit of the electrosurgical generator 137426,which then compares the received signal (which is indicative of theforce F or pressure experienced by the FSR 137421) to a threshold todetermine whether to activate electrosurgical generator 137426. If thereceived signal does exceed the threshold, the control circuit of theelectrosurgical generator 137426 can cause the electrosurgical generator137426 to begin suppling energy (via, e.g., a drive signal) to thetransducer assembly 137510 of the surgical instrument 137400 that iselectrically connected thereto. In sum, in some aspects the controlcircuit 137506 can determine whether a sufficient amount of force isbeing applied to the touch sensor 137420 and then activate thetransducer assembly 137510 accordingly.

FIGS. 135A-C illustrate perspective views of a surgical instrument137400 including a sensor assembly 137429 configured to detect closureof the surgical instrument 137400, in accordance with at least oneaspect of the present disclosure. In the following description of FIGS.135A-C, reference should also be made to FIG. 130 . In one aspect, theclosure sensor assembly 137429 can include a closure sensor 137430configured to detect when the arm 137412 of the surgical instrument137400 is in a closed position and, in some aspects, whether additionalforce is being applied to the arm 137412 after the surgical instrument137400 is in the closed position. In one exemplification, the closuresensor 137430 comprises a two-stage tactile switch that is configured todetect, at a first stage, when the arm of the surgical instrument is ina closed position and, further, is configured to detect, at a secondstage, when additional force or pressure is being applied after the arm137412 of the surgical instrument 137400 is in the closed position. Sucha closure sensor 137430 can be utilized to, for example, allow thesurgical instrument 137400 to be closed without necessarilyautomatically activating the transducer assembly 137510 and/or RFelectrodes 796.

In one aspect depicted in FIGS. 135A-C, the closure sensor 137430 ispositioned on the housing 137414 such that the arm 137412 engages theclosure sensor 137430 when the arm 137412 is rotated in a firstdirection R₁ into a closed position, as shown in FIG. 135B, from an openposition, as shown in FIG. 135A. When the arm 137412 is in the closedposition, the arm 137412 can bottom out against the housing 137414(shroud) and/or the closure sensor 137430. When the surgical instrument137400 is opened (or otherwise not closed) or when the arm 137412 of thesurgical instrument 137400 is closed, but no additional force is beingapplied thereto, the closure sensor 137430 can be in the first positionor the first state, as depicted in FIG. 135B. When the arm 137412 of thesurgical instrument 137400 is closed and an additional force F₁ isapplied to the arm 137412, the closure sensor 137430 can be in thesecond position or the second state, as depicted in FIG. 135C. In someaspects, when the arm 137412 is in the initial closed position, the arm137412 can be at a first angle θ₁ from the housing 137414, and when aforce F₁ is applied to the arm 137412 in the initial closed position,the force F₁ can cause the closure sensor 137430 to depress, such thatthe arm 137412 is a second angle θ₂ from the housing 137414.

In one aspect, the output of the closure sensor 137430 can varyaccording to the position and/or state that the closure sensor 137430 isin. In other words, when the closure sensor 137430 is in the firststate, it can provide a first output to the control circuit 137506 ofthe surgical instrument 137400, and when the closure sensor 137430 is inthe second state, it can provide a second output to the control circuit137506 of the surgical instrument 137400. Thus, the closure sensor137430 can be configured to detect whether (i) the surgical instrument137400 is closed and (ii) when the surgical instrument 137400 is closed,whether additional force is being applied. In one aspect, the transducerassembly 137510 and/or RF electrodes 796 can be activated and/orsupplied energy only when the closure sensor 137430 is in the secondstate/position. This aspect would allow surgeons to activate thesurgical instrument 137400 solely through manipulation of the arm137412, but without losing the ability to grasp and manipulate tissueabsent activation of the activation of the transducer assembly 137510and/or RF electrodes 796.

In one aspect, the control circuit 137506 is configured to receive theoutput from the closure sensor 137430 and then compare the output of theclosure sensor 137430 to a threshold to determine whether the closuresensor 137430 is in the second position/state. The threshold can be,e.g., predetermined or set by a user of the surgical instrument 137400.In the exemplifications described above where the closure sensor 137430detects whether the arm 137412 of the surgical instrument 137400 isbeing closed and, further, whether additional force is being applied tothe arm 137412 when the arm 137412 is closed, the output of the closuresensor 137430 thus varies accordingly. Further in theseexemplifications, the threshold can correspond to a threshold forcebeing applied to the arm 137412 (and thus the closure sensor 137430)after the arm 137412 is closed. For example, if the control circuit137506 determines that the closure sensor 137430 output exceeds thethreshold, then the control circuit 137506 can activate the transducerassembly 137510 and/or RF electrodes 796 by sending a signal to thegenerator 137504 that cause the generator 137504 to begin supplyingenergy to the transducer assembly. In sum, in some aspects the controlcircuit 137506 can determine whether a sufficient amount of force isbeing applied to the closed arm 137412 of the surgical instrument 137400and, if it is, then activate the transducer assembly 137510 and/or RFelectrodes 796.

FIGS. 136A-F illustrates various views of a surgical instrument 137400including a sensor assembly 137439 configured to detect opening of thesurgical instrument 137400, in accordance with at least one aspect ofthe present disclosure. In the following description of FIGS. 136A-F,reference should also be made to FIG. 130 . In one aspect, the openingsensor assembly 137439 includes an opening sensor 137440 that isconfigured to detect when the arm 137412 of the surgical instrument137400 is rotated in a second direction R₂ into an open position. In oneexemplification, the opening sensor 137440 comprises a tactile switch(e.g., a one-stage tactile switch) that is configured to detect when thearm 137412 of the surgical instrument 137400 is in a sufficiently openposition. The opening sensor 137440 can be utilized to, for example,allow the surgical instrument 137400 to be energized when it is in afully or sufficiently open position for performing back (anterior)scoring and other such surgical techniques that utilize the applicationof electrosurgical or ultrasonic energy to unclamped tissue, withoutcausing the surgical instrument 137400 to be energized any time thesurgical instrument 137400 is opened to any degree.

In various aspects, the opening sensor 137440 can be positioned at oradjacently to the pivot point 137413 of the surgical instrument 137400.In one aspect depicted in FIGS. 136A-F, the opening sensor 137440 ispositioned within a recess 137443 on a first lateral portion of thehousing 137414. A corresponding tab 137442 is positioned on a secondlateral portion of the housing 137414 and is configured to move throughthe recess 137443 and contact the opening sensor 137440, applying aforce F₂ thereto, when the clamp arm 137416 of the surgical instrument137400 is sufficiently open (i.e., opened to at least a particularangle). When the opening sensor 137440 is uncontacted by the tab 137442,the opening sensor 137440 can be in the first position or the firststate. When the arm 137412 of the surgical instrument 137400 is openedto a sufficient angle such that the tab 137422 contacts the openingsensor 137440, the opening sensor 137440 can be in the second positionor the second state, as depicted in FIG. 136D. In one aspect, the outputof the opening sensor 137440 can vary according to the position and/orstate that the opening sensor 137440 is in. In other words, when theopening sensor 137440 is in the first state, it can provide a firstoutput to the control circuit 137506 of the surgical instrument 137400,and when the opening sensor 137440 is in the second state, it canprovide a second output to the control circuit 137506 of the surgicalinstrument 137400. Thus, the opening sensor 137440 is able to detectwhether the surgical instrument 137400 is opened at least to the anglethat causes the opening sensor 137440 to be triggered or activated(e.g., by a force F₂ being applied thereto). In one aspect, thetransducer assembly 137510 and/or RF electrodes 796 can be activatedand/or energized, as described above, only when the sensor is in thesecond state/position.

In one aspect, the control circuit 137506 is configured to receive theoutput from the opening sensor 137440 and then compare the output of theopening sensor 137440 to a threshold, where the threshold corresponds tothe opening sensor 137440 being in the second position/state. Thethreshold can be, e.g., predetermined or set by a user of the surgicalinstrument 137400. In the exemplifications described above where theopening sensor 137440 detects whether the arm 137412 of the surgicalinstrument 137400 is open to a particular angle, the output of theopening sensor 137440 thus varies accordingly. Further in theseexemplifications, the threshold can correspond to a threshold angle atwhich the arm 137412 of the surgical instrument 137400 is positioned. Inone aspect, if the control circuit 137506 determines that the output ofthe opening sensor 137440 exceeds the threshold, then the controlcircuit 137506 can activate the transducer assembly 137510 and/or RFelectrodes 796 by sending a signal to the generator 137504 that causethe generator 137504 to begin supplying energy to the transducerassembly 137510 and/or RF electrodes 796. In sum, in some aspects thecontrol circuit 137506 can determine whether the arm 137412 of thesurgical instrument 137400 is open to a sufficient angle and, if it is,then activate the transducer assembly 137510 and/or RF electrodes 796.

In certain aspects, the sensor assemblies for activating a surgicalinstrument 137400 described above in connection with FIGS. 131-136F canbe implemented in various combinations with each other. For example,FIG. 137 illustrates an exemplification of a surgical instrument 137400where the sensor assembly 137508 includes both the closure sensorassembly 137429 described in connection with FIGS. 135A-C and theopening sensor assembly 137439 described in connection with FIGS.136A-F. The various aspects of sensor assemblies 137508 described hereincan be combined together in a surgical instrument 137400 in order toprovide supplementary and/or alternative methods for activating and/orproviding input to the surgical instrument 137400. It should be notedthat the exemplification depicted in FIG. 137 is intended to be merelyillustrative and other exemplifications of surgical instruments 137400can include any other combination of the aforementioned sensorassemblies 137508.

FIG. 138 illustrates a perspective view of a surgical instrumentcomprising a deactivation control 137450, in accordance with at leastone aspect of the present disclosure. In various aspects, the surgicalinstrument 137400 can include a deactivation control 137450 forcontrolling whether one or more of the various sensors of the surgicalinstrument 137400, such as various sensor assemblies 137508 describedabove with respect to FIGS. 131-136F, are active. The deactivationcontrol 137450 can include, for example, a physical toggle or switchdisposed on the housing 137414 of the surgical instrument 137400 or atouchscreen display. The deactivation control 137450 can be communicablycoupled to the control circuit 137506 of the surgical instrument 137400and, depending upon the input from the deactivation control 137450, thecontrol circuit 137506 can, for example, deactivate the sensor assembly137508 controlled by the deactivation control 137450 or otherwise ignorethe output of or not take any actions in response to the output from thesensor assembly 137508 controlled by the deactivation control 137450.

In reference to FIGS. 128-138 , the surgical instrument 137400 canfurther include an indicator, such as an LED, a display, and other suchoutput devices. The indicator can be coupled to the control circuit137506 and controlled thereby. In some aspects, the control circuit137506 can be configured to activate the indicator in response to aninput received from the sensor assembly 137508. For example, the controlcircuit 137506 can be configured to activate the indicator when thecontrol circuit 137506 determines that the surgical instrument 137400 isin a closed position (e.g., as sensed via a sensor assembly 137508).

Smart Retractor

FIG. 139 illustrates a perspective view of a retractor 137600 comprisinga sensor 137602, in accordance with at least one aspect of the presentdisclosure. In various aspects, a retractor 137600 for securing asurgical site opening 137650 can include a sensor 137602 that isremovably or integrally affixed thereto. In one aspect, the sensor137602 is removably affixable to the retractor 137600 via a magnet. Thesensor 137602 can be configured to detect when the retractor 137600 istapped, jostled, moved, or otherwise manipulated by a user (e.g., asurgeon). In one exemplification, the sensor 137602 can include avibration sensor (e.g., an ADIS16223 digital tri-axial vibration sensor)that is configured to detect vibration or movement by the retractor137600 to which the sensor 137602 is affixed. In one aspect, the sensor137602 can be reusable, i.e., the sensor 137602 can maintain itseffectiveness through sterilization processes (because the sensor 137602is affixed to a retractor 137600, which is in the surgical field, itwould be sterilized after being used in a surgical procedure if it wasto be reused). The sensor 137602 can be configured to detect differenttypes of motions or actions (e.g., tapping) by a user according to theamplitude, frequency, and/or direction of the detected motion orvibration of the retractor 137600.

The sensor 137602 can be configured to transmit a signal indicative ofthe detected vibration or movement of the retractor 137600. In oneaspect, the sensor 137602 can be communicably coupled to a surgicalinstrument 137606 (e.g., a surgical instrument or an electrosurgicalinstrument) and/or another device (e.g., a generator) via, for example,a wired connection 137604. Based upon the motion or movement detected bythe sensor 137602, the sensor 137602 can change the state of thesurgical instrument(s) 137606 and/or other device(s) that arecommunicably coupled to the sensor 137602. The state of the surgicalinstrument(s) 137606 and/or other device(s) can correspond to, forexample, a mode that the instrument(s) 137606 and/or device(s) are in ora property of the instrument(s) 137606 and/or device(s). For example,when the sensor 137602 detects that the retractor 137600 is beingtapped, the sensor 137602 can transmit a signal to a surgical instrument137606 that is communicably coupled with it that causes the surgicalinstrument to 137606 to change from an inactive state to an activatestate (or vice versa). As another example, when the sensor 137602detects that the retractor 137600 is being touched, the sensor 137602can transmit a signal to a surgical generator that is communicablycoupled with it that causes the generator to change from an inactivemode to an activate mode (or vice versa). In some aspects, the retractorsensor 137602 can be configured to transmit data and/or signals to asurgical hub 106, as described in connection with FIGS. 1-11 , which canthen in turn take various actions, such as controlling the surgicalinstrument(s) 137606 and/or other device(s), as described above.

FIG. 140 illustrates a perspective view of a retractor 137902 comprisinga display in use at a surgical site 137900, in accordance with at leastone aspect of the present disclosure. A surgical retractor 137902 helpsthe surgeon and operating room professionals hold an incision or woundopen during surgical procedures. The surgical retractor 137902 aids inholding back underlying organs or tissues, allowing doctors/nursesbetter visibility and access to the exposed area. A retractor 137902 caninclude a display 137904 or other control device that is configured todisplay alerts and/or information associated with the surgical procedurebeing performed, provide a means of controlling the instruments ordevices being utilized during the course of the surgical procedure orthe environment in which the surgical procedure is being performed(e.g., the operating room), and perform other such functions. In thedepicted aspect, the control device is integral to the retractor 137902.In another aspect, the control device can include, for example, aportable electronic device including a touchscreen display (e.g., atablet computer) that is removably affixable to the retractor 137902. Inyet another aspect, the control device includes a flexible stickerdisplay that is attachable to the body/skin of the patient or anothersurface

In one aspect, the control device includes an input device (e.g., akeypad, a capacitive touchscreen, or a combination thereof) forreceiving input from a user, an output device (e.g., a display) forproviding alerts, information, or other output to a user, an energysource (e.g., a coin cell, a battery, a photovoltaic cell, or acombination thereof); and a network interface controller for acommunication protocol (e.g., Wi-Fi, Bluetooth) for communicablyconnecting the control device to surgical instruments, devices withinthe operating room (e.g., a surgical hub 106 as described in FIGS. 1-11), and/or other equipment (surgical or otherwise). The control devicecan be configured to provide a graphical user interface (GUI) fordisplaying information to the user (e.g., a surgeon) and receiving inputor commands from the user. In one aspect, the control device furtherincludes a light source 137906 (e.g., an array of LEDs) that isconfigured to illuminate the surgical field of view 137908 that theretractor 137902 is being utilized to secure.

In one aspect, the control device is removably affixable to the surgicalretractor 137902. In another aspect, the control device is integral tothe retractor 137902, defining a “smart” surgical retractor 137902. Thesmart surgical retractor 137902 may comprise an input display operatedby the smart surgical retractor 137902. The smart surgical retractor137902 may comprise a wireless communication device to communicate witha device connected to a generator module coupled to the surgical hub.Using the input display of the smart surgical retractor 137902, thesurgeon can adjust power level or mode of the generator module to cutand/or coagulate tissue. If using automatic on/off for energy deliveryon closure of an end effector on the tissue, the status of automaticon/off may be indicated by a light, screen, or other device located onthe smart retractor housing. Power being used may be changed anddisplayed.

In various aspects, the control device can be configured to controlvarious functions of the surgical instruments that are communicablyconnected to the control device, such as the power parameters (e.g., foran electrosurgical instrument and/or an ultrasonic instrument) oroperating modes (e.g., “cut” and “coagulation” modes for anelectrosurgical instrument, or automatic) of the surgical instruments.In various aspects, the control device can be configured to displayinformation related to the surgical procedure being performed and/orinformation related to the equipment being used during the course of thesurgical procedure, such as the temperature of an ultrasonic blade (endeffector), alerts or alarms that are generated during the course of thesurgical procedure, or the location of nerves within the surgical field.The alerts or alarms can be generated by, for example, the surgicalinstruments and/or a surgical hub 106 to which the surgical instruments(or other modular surgical devices) are communicably connected. Invarious aspects, the control device can be configured to controlfunctions of the environment in which the surgical procedure is beingperformed (e.g., an operating room), such as the intensity and/orposition of the field lights within an operating room.

In various aspects, the control device can be configured to sense whatsurgical instruments or other equipment are within the vicinity of thecontrol device and then cause any surgical instruments or otherequipment that connected to the control device to pass their operationalcontrols to the control device. In one aspect, the smart surgicalretractor 137902 can sense or know what device/instrument the surgeon isusing, either through the surgical hub 106 or RFID or other deviceplaced on the device/instrument or the smart surgical retractor 137902,and provide an appropriate display. Alarms and alerts may be activatedwhen conditions require. Other features include displaying thetemperature of the ultrasonic blade, nerve monitoring, light source orfluorescence. The light source 137906 may be employed to illuminate thesurgical field of view 137908 and to charge photocells on single usesticker display that stick onto the smart retractor 137902. In anotheraspect, the smart surgical retractor 137902 may include an augmentedreality projected on the patient's anatomy (e.g., a vein viewer).

In other aspects, the control device can comprise a smart flexiblesticker display attachable to the body/skin of a patient. The smartflexible sticker display can be applied to, for example, the body/skinof a patient between the area exposed by the surgical retractors. In oneaspect, the smart flexible sticker display may be powered by light, anon board battery, or a ground pad. The flexible sticker display maycommunicate via short range wireless (e.g., Bluetooth) to a device, mayprovide readouts, lock power, or change power. The smart flexiblesticker display also comprises photocells to power the smart flexiblesticker display using ambient light energy. The flexible sticker displayincludes a display 137904 of a control panel user interface to enablethe surgeon to control devices or other modules coupled to the surgicalhub.

Various additional details regarding smart retractors can be found inU.S. patent application Ser. No. 15/940,686, titled DISPLAY OF ALIGNMENTOF STAPLE CARTRIDGE TO PRIOR LINEAR STAPLE LINE, filed Mar. 29, 2018,which is hereby incorporated by reference in its entirety.

Situational Awareness of Electrosurgical Systems

Electrosurgical instruments are utilized to treat various tissue typesby application of energy to the tissue. As described in connection withFIGS. 22-24 , an electrosurgical instrument (e.g. surgical instruments1104, 1106, 1108) may be connected to a generator 1100, and include anend effector (e.g. end effectors 1122, 1124, 1125) configured to graspand transmit therapeutic energy to tissue.

In various aspects, the end effector can be used to seal, weld, orcoagulate tissue such as, for example, a blood vessel by application ofenergy to the blood vessel while grasped by the end effector. Sinceblood vessels are generally surrounded by protective tissue, the tissuehas to be separated to expose the blood vessels for an effective seal tobe achieved. But tissue separation requires lower energy than tissuesealing or coagulation. Also, the amount of tissue to be separatedvaries depending on, for example, the anatomical location of the bloodvessel, the state of the tissue, and the type of surgery beingperformed.

One technique of treating a tissue that includes a blood vessel involvesseparating and moving the inner muscle layer of the blood vessel awayfrom the adventitia layer prior to sealing and/or transecting the bloodvessel. In order to more effectively separate the tissue layers of theblood vessel, a low level energy sufficient to separate but notcoagulate or seal the tissue can be generated and transmitted to thetissue. Subsequently, a high level energy is employed to seal orcoagulate the tissue.

A successful energy treatment of tissue grasped by an end effectordepends on selecting a suitable energy mode of operation for eachclosure stage of the end effector. Furthermore, closure stages of an endeffector may be determined by various situational parameters such as,for example, tissue type, anatomical location, and/or composition.Various suitable situational parameters are described under the heading“SITUATIONAL AWARENESS” in connection with FIG. 141 .

Aspects of the present disclosure present various processes forselecting different energy modes for different closure stages of an endeffector of an electrosurgical instrument. The selection can be based,at least in part, on one or more situational parameters.

Situational Awareness

Situational awareness is the ability of some aspects of a surgicalsystem to determine or infer information related to a surgical procedurefrom data received from databases and/or instruments. The informationcan include the type of procedure being undertaken, the type of tissuebeing operated on, or the body cavity that is the subject of theprocedure. With the contextual information related to the surgicalprocedure, the surgical system can, for example, improve the manner inwhich it controls the modular devices (e.g. a robotic arm and/or roboticsurgical tool) that are connected to it and provide contextualizedinformation or suggestions to the surgeon during the course of thesurgical procedure.

Referring now to FIG. 141 , a timeline 5200 depicting situationalawareness of a hub, such as the surgical hub 106 or 206, for example, isdepicted. The timeline 5200 is an illustrative surgical procedure andthe contextual information that the surgical hub 106, 206 can derivefrom the data received from the data sources at each step in thesurgical procedure. The timeline 5200 depicts the typical steps thatwould be taken by the nurses, surgeons, and other medical personnelduring the course of a lung segmentectomy procedure, beginning withsetting up the operating theater and ending with transferring thepatient to a post-operative recovery room.

The situationally aware surgical hub 106, 206 receives data from thedata sources throughout the course of the surgical procedure, includingdata generated each time medical personnel utilize a modular device thatis paired with the surgical hub 106, 206. The surgical hub 106, 206 canreceive this data from the paired modular devices and other data sourcesand continually derive inferences (i.e., contextual information) aboutthe ongoing procedure as new data is received, such as which step of theprocedure is being performed at any given time. The situationalawareness system of the surgical hub 106, 206 is able to, for example,record data pertaining to the procedure for generating reports, verifythe steps being taken by the medical personnel, provide data or prompts(e.g., via a display screen) that may be pertinent for the particularprocedural step, adjust modular devices based on the context (e.g.,activate monitors, adjust the field of view (FOV) of the medical imagingdevice, or change the energy level of an ultrasonic surgical instrumentor RF electrosurgical instrument), and take any other such actiondescribed above.

As the first step 5202 in this illustrative procedure, the hospitalstaff members retrieve the patient's EMR from the hospital's EMRdatabase. Based on select patient data in the EMR, the surgical hub 106,206 determines that the procedure to be performed is a thoracicprocedure.

Second step 5204, the staff members scan the incoming medical suppliesfor the procedure. The surgical hub 106, 206 cross-references thescanned supplies with a list of supplies that are utilized in varioustypes of procedures and confirms that the mix of supplies corresponds toa thoracic procedure. Further, the surgical hub 106, 206 is also able todetermine that the procedure is not a wedge procedure (because theincoming supplies either lack certain supplies that are necessary for athoracic wedge procedure or do not otherwise correspond to a thoracicwedge procedure).

Third step 5206, the medical personnel scan the patient band via ascanner that is communicably connected to the surgical hub 106, 206. Thesurgical hub 106, 206 can then confirm the patient's identity based onthe scanned data.

Fourth step 5208, the medical staff turns on the auxiliary equipment.The auxiliary equipment being utilized can vary according to the type ofsurgical procedure and the techniques to be used by the surgeon, but inthis illustrative case they include a smoke evacuator, insufflator, andmedical imaging device. When activated, the auxiliary equipment that aremodular devices can automatically pair with the surgical hub 106, 206that is located within a particular vicinity of the modular devices aspart of their initialization process. The surgical hub 106, 206 can thenderive contextual information about the surgical procedure by detectingthe types of modular devices that pair with it during this pre-operativeor initialization phase. In this particular example, the surgical hub106, 206 determines that the surgical procedure is a VATS procedurebased on this particular combination of paired modular devices. Based onthe combination of the data from the patient's EMR, the list of medicalsupplies to be used in the procedure, and the type of modular devicesthat connect to the hub, the surgical hub 106, 206 can generally inferthe specific procedure that the surgical team will be performing. Oncethe surgical hub 106, 206 knows what specific procedure is beingperformed, the surgical hub 106, 206 can then retrieve the steps of thatprocedure from a memory or from the cloud and then cross-reference thedata it subsequently receives from the connected data sources (e.g.,modular devices and patient monitoring devices) to infer what step ofthe surgical procedure the surgical team is performing.

Fifth step 5210, the staff members attach the EKG electrodes and otherpatient monitoring devices to the patient. The EKG electrodes and otherpatient monitoring devices are able to pair with the surgical hub 106,206. As the surgical hub 106, 206 begins receiving data from the patientmonitoring devices, the surgical hub 106, 206 thus confirms that thepatient is in the operating theater.

Sixth step 5212, the medical personnel induce anesthesia in the patient.The surgical hub 106, 206 can infer that the patient is under anesthesiabased on data from the modular devices and/or patient monitoringdevices, including EKG data, blood pressure data, ventilator data, orcombinations thereof, for example. Upon completion of the sixth step5212, the pre-operative portion of the lung segmentectomy procedure iscompleted and the operative portion begins.

Seventh step 5214, the patient's lung that is being operated on iscollapsed (while ventilation is switched to the contralateral lung). Thesurgical hub 106, 206 can infer from the ventilator data that thepatient's lung has been collapsed, for example. The surgical hub 106,206 can infer that the operative portion of the procedure has commencedas it can compare the detection of the patient's lung collapsing to theexpected steps of the procedure (which can be accessed or retrievedpreviously) and thereby determine that collapsing the lung is the firstoperative step in this particular procedure.

Eighth step 5216, the medical imaging device (e.g., a scope) is insertedand video from the medical imaging device is initiated. The surgical hub106, 206 receives the medical imaging device data (i.e., video or imagedata) through its connection to the medical imaging device. Upon receiptof the medical imaging device data, the surgical hub 106, 206 candetermine that the laparoscopic portion of the surgical procedure hascommenced. Further, the surgical hub 106, 206 can determine that theparticular procedure being performed is a segmentectomy, as opposed to alobectomy (note that a wedge procedure has already been discounted bythe surgical hub 106, 206 based on data received at the second step 5204of the procedure). The data from the medical imaging device 124 (FIG. 2) can be utilized to determine contextual information regarding the typeof procedure being performed in a number of different ways, including bydetermining the angle at which the medical imaging device is orientedwith respect to the visualization of the patient's anatomy, monitoringthe number or medical imaging devices being utilized (i.e., that areactivated and paired with the surgical hub 106, 206), and monitoring thetypes of visualization devices utilized. For example, one technique forperforming a VATS lobectomy places the camera in the lower anteriorcorner of the patient's chest cavity above the diaphragm, whereas onetechnique for performing a VATS segmentectomy places the camera in ananterior intercostal position relative to the segmental fissure. Usingpattern recognition or machine learning techniques, for example, thesituational awareness system can be trained to recognize the positioningof the medical imaging device according to the visualization of thepatient's anatomy. As another example, one technique for performing aVATS lobectomy utilizes a single medical imaging device, whereas anothertechnique for performing a VATS segmentectomy utilizes multiple cameras.As yet another example, one technique for performing a VATSsegmentectomy utilizes an infrared light source (which can becommunicably coupled to the surgical hub as part of the visualizationsystem) to visualize the segmental fissure, which is not utilized in aVATS lobectomy. By tracking any or all of this data from the medicalimaging device, the surgical hub 106, 206 can thereby determine thespecific type of surgical procedure being performed and/or the techniquebeing used for a particular type of surgical procedure.

Ninth step 5218, the surgical team begins the dissection step of theprocedure. The surgical hub 106, 206 can infer that the surgeon is inthe process of dissecting to mobilize the patient's lung because itreceives data from the RF or ultrasonic generator indicating that anenergy instrument is being fired. The surgical hub 106, 206 cancross-reference the received data with the retrieved steps of thesurgical procedure to determine that an energy instrument being fired atthis point in the process (i.e., after the completion of the previouslydiscussed steps of the procedure) corresponds to the dissection step. Incertain instances, the energy instrument can be an energy tool mountedto a robotic arm of a robotic surgical system.

Tenth step 5220, the surgical team proceeds to the ligation step of theprocedure. The surgical hub 106, 206 can infer that the surgeon isligating arteries and veins because it receives data from the surgicalstapling and cutting instrument indicating that the instrument is beingfired. Similarly to the prior step, the surgical hub 106, 206 can derivethis inference by cross-referencing the receipt of data from thesurgical stapling and cutting instrument with the retrieved steps in theprocess. In certain instances, the surgical instrument can be a surgicaltool mounted to a robotic arm of a robotic surgical system.

Eleventh step 5222, the segmentectomy portion of the procedure isperformed. The surgical hub 106, 206 can infer that the surgeon istransecting the parenchyma based on data from the surgical stapling andcutting instrument, including data from its cartridge. The cartridgedata can correspond to the size or type of staple being fired by theinstrument, for example. As different types of staples are utilized fordifferent types of tissues, the cartridge data can thus indicate thetype of tissue being stapled and/or transected. In this case, the typeof staple being fired is utilized for parenchyma (or other similartissue types), which allows the surgical hub 106, 206 to infer that thesegmentectomy portion of the procedure is being performed.

Twelfth step 5224, the node dissection step is then performed. Thesurgical hub 106, 206 can infer that the surgical team is dissecting thenode and performing a leak test based on data received from thegenerator indicating that an RF or ultrasonic instrument is being fired.For this particular procedure, an RF or ultrasonic instrument beingutilized after parenchyma was transected corresponds to the nodedissection step, which allows the surgical hub 106, 206 to make thisinference. It should be noted that surgeons regularly switch back andforth between surgical stapling/cutting instruments and surgical energy(i.e., RF or ultrasonic) instruments depending upon the particular stepin the procedure because different instruments are better adapted forparticular tasks. Therefore, the particular sequence in which thestapling/cutting instruments and surgical energy instruments are usedcan indicate what step of the procedure the surgeon is performing.Moreover, in certain instances, robotic tools can be utilized for one ormore steps in a surgical procedure and/or handheld surgical instrumentscan be utilized for one or more steps in the surgical procedure. Thesurgeon(s) can alternate between robotic tools and handheld surgicalinstruments and/or can use the devices concurrently, for example. Uponcompletion of the twelfth step 5224, the incisions are closed up and thepost-operative portion of the procedure begins.

Thirteenth step 5226, the patient's anesthesia is reversed. The surgicalhub 106, 206 can infer that the patient is emerging from the anesthesiabased on the ventilator data (i.e., the patient's breathing rate beginsincreasing), for example.

Lastly, the fourteenth step 5228 is that the medical personnel removethe various patient monitoring devices from the patient. The surgicalhub 106, 206 can thus infer that the patient is being transferred to arecovery room when the hub loses EKG, BP, and other data from thepatient monitoring devices. As can be seen from the description of thisillustrative procedure, the surgical hub 106, 206 can determine or inferwhen each step of a given surgical procedure is taking place accordingto data received from the various data sources that are communicablycoupled to the surgical hub 106, 206.

Situational awareness is further described in U.S. Provisional PatentApplication Ser. No. 62/611,341, titled INTERACTIVE SURGICAL PLATFORM,filed Dec. 28, 2017, which is herein incorporated by reference in itsentirety. In certain instances, operation of a robotic surgical system,including the various robotic surgical systems disclosed herein, forexample, can be controlled by the hub 106, 206 based on its situationalawareness and/or feedback from the components thereof and/or based oninformation from the cloud 102.

EXAMPLES

Various aspects of the subject matter described herein are set out inthe following numbered examples.

Example 1: A method for characterizing a state of an end effector of anultrasonic device, the ultrasonic deice comprising an electromechanicalultrasonic system defined by a predetermined resonant frequency, theelectromechanical ultrasonic system further comprising an ultrasonictransducer coupled to an ultrasonic blade, the method comprising:applying, by an energy source, a power level to the ultrasonictransducer, measuring, by a control circuit coupled to a memory, animpedance value of the ultrasonic transducer, comparing, by the controlcircuit, the impedance value to a reference impedance value stored inthe memory; classifying, by the control circuit, the impedance valuebased on the comparison; characterizing, by the control circuit, thestate of the electromechanical ultrasonic system based on theclassification of the impedance value; and adjusting, by the controlcircuit, the power level applied to the ultrasonic transducer based onthe characterization of the state of the end effector.

Example 2: The method of Example 1, wherein measuring, by a controlcircuit coupled to a memory, an impedance value of the ultrasonictransducer comprises measuring a complex impedance value defined as aratio of a voltage signal Vg(t) applied by the energy source to theultrasonic transducer to a current signal Ig(t) applied by the energysource to the ultrasonic transducer.

Example 3: The method of Example 2, wherein comparing, by the controlcircuit, the impedance value to a reference impedance value stored inthe memory comprises comparing, by the control circuit, the impedancevalue to a data point in a reference complex impedance characteristicpattern.

Example 4: The method of any one or more of Examples 1-3, whereinmeasuring, by a control circuit coupled to a memory, an impedance valueof the ultrasonic transducer comprises: applying, by the energy source,a drive signal to the ultrasonic transducer, wherein the drive signal isa periodic signal defined by a magnitude and a frequency; sweeping, bythe control circuit, the frequency of the drive signal from below afirst resonance to above the first resonance of the electromechanicalultrasonic system; and measuring and recording, by the control circuit,impedance/admittance circle variables Re, Ge, Xe, and Be.

Example 5: The method of Example 4, wherein comparing, by the controlcircuit, the impedance value to reference impedance value stored in thememory comprises comparing, by the control circuit, the measuredimpedance/admittance circle variables Re, Ge, Xe, Be to the referenceimpedance/admittance circle variables Rref, Gref, Xref, and Bref.

Example 6: The method of any one or more of Examples 1-5, whereincharacterizing, by the control circuit, the state of theelectromechanical ultrasonic system based on the classification of theimpedance value comprises determining the proper installation of two ormore components of the ultrasonic device.

Example 7: The method of any one or more of Examples 1-6, whereincharacterizing, by the control circuit, the state of theelectromechanical ultrasonic system based on the classification of theimpedance value comprises determining an amount of power delivered tothe ultrasonic device by the energy source to compensate for anarticulation angle of an articulatable ultrasonic blade coupled to theultrasonic transducer.

Example 8: A method for characterizing a function of an end effector ofan ultrasonic device, the ultrasonic deice comprising anelectromechanical ultrasonic system defined by a predetermined resonantfrequency, the electromechanical ultrasonic system further comprising anultrasonic transducer coupled to an ultrasonic blade, the methodcomprising: applying, by an energy source, a power level to theultrasonic transducer, measuring, by a control circuit coupled to amemory, an impedance value of the ultrasonic transducer, comparing, bythe control circuit, the impedance value to a reference impedance valuestored in the memory; classifying, by the control circuit, the impedancevalue based on the comparison; characterizing, by the control circuit,the function of the electromechanical ultrasonic system based on theclassification of the impedance value; and adjusting, by the controlcircuit, the power level applied to the ultrasonic transducer based onthe characterization of the function of the end effector.

Example 9: The method of Example 8, wherein measuring, by a controlcircuit coupled to a memory, an impedance value of the ultrasonictransducer comprises measuring a complex impedance value defined as aratio of a voltage signal Vg(t) applied by the energy source to theultrasonic transducer to a current signal Ig(t) applied by the energysource to the ultrasonic transducer.

Example 10: The method of Example 9, wherein comparing, by the controlcircuit, the impedance value to a reference impedance value stored inthe memory comprises comparing, by the control circuit, the impedancevalue to a data point in a reference complex impedance characteristicpattern.

Example 11: The method of any one or more of Examples 8-10, whereinadjusting, by the control circuit, the power level applied to theultrasonic transducer based on the characterization of the function ofthe end effector comprises adjusting, by the control circuit, the powerlevel applied to the ultrasonic transducer based on a determination thata tissue transection process is complete.

Example 12: The method of any one or more of Examples 8-11, whereincharacterizing, by the control circuit, the function of theelectromechanical ultrasonic system based on the classification of theimpedance value comprises determining, by the control circuit, that theultrasonic blade is contacting a vessel.

Example 13: The method of Example 12, wherein measuring, by a controlcircuit coupled to a memory, an impedance value of the ultrasonictransducer comprises measuring, by the control circuit, a compleximpedance of the ultrasonic transducer, wherein the complex impedance isdefined as

${Z_{g}(t)} = {\frac{V_{g}(t)}{I_{g}(t)}.}$

Example 14: The method of Example 13, further comprising: receiving, bythe control circuit, a complex impedance measurement data point;comparing, by the control circuit, the complex impedance measurementdata point to a data point in a reference complex impedancecharacteristic pattern; classifying, by the control circuit, the compleximpedance measurement data point based on a result of the comparisonanalysis; and determining, by the control circuit, that the ultrasonicblade is contacting the vessel based on the result of the comparisonanalysis.

Example 15: The method of any one or more of Examples 12-14, furthercomprising generating, by the control circuit, a warning that theultrasonic blade is contacting the vessel.

Example 16: A method for characterizing a tissue in contact with an endeffector of an ultrasonic device, the ultrasonic deice comprising anelectromechanical ultrasonic system defined by a predetermined resonantfrequency, the electromechanical ultrasonic system further comprising anultrasonic transducer coupled to an ultrasonic blade, the methodcomprising: applying, by an energy source, a power level to theultrasonic transducer, measuring, by a control circuit coupled to amemory, an impedance value of the ultrasonic transducer, comparing, bythe control circuit, the impedance value to a reference impedance valuestored in the memory; classifying, by the control circuit, the impedancevalue based on the comparison; characterizing, by the control circuit,the tissue in contact with the end effector based on the classificationof the impedance value; and adjusting, by the control circuit, the powerlevel applied to the ultrasonic transducer based on the characterizationof the tissue in contact with the end effector.

Example 17: The method of Example 16, wherein measuring, by a controlcircuit coupled to a memory, an impedance value of the ultrasonictransducer comprises measuring a complex impedance value defined as aratio of a voltage signal Vg(t) applied by the energy source to theultrasonic transducer to a current signal Ig(t) applied by the energysource to the ultrasonic transducer.

Example 18: The method of Example 17, further comprising: pulsing, bythe control circuit, the power level delivered to the ultrasonictransducer by the energy source; determining, by the control circuit,changes in tissue characteristics of tissue located in the end effector,wherein the changes in tissue characteristics is determined betweenpulses; and adjusting, by the processor or control circuit, powerdelivered to the ultrasonic transducer based on the tissue changes.

Example 19: The method of any one or more of Examples 16-18, whereinmeasuring, by a control circuit coupled to a memory, an impedance valueof the ultrasonic transducer comprises: applying, by the energy source,a drive signal to the ultrasonic transducer, wherein the drive signal isa periodic signal defined by a magnitude and a frequency; sweeping, bythe control circuit, the frequency of the drive signal from below afirst resonance to above the first resonance of the electromechanicalultrasonic system; and measuring and recording, by the control circuit,impedance/admittance circle variables Re, Ge, Xe, and Be.

Example 20: The method of claim any one or more of Examples 16-19,wherein characterizing, by the control circuit, the tissue in contactwith the end effector based on the classification of the impedance valuecomprises classifying the tissue into a distinct group in live time.

Various additional aspects of the subject matter described herein areset out in the following numbered examples.

Example 1: A surgical system comprising: an energy generator, a surgicalinstrument electrically coupled to the energy generator and configuredto transmit electrosurgical energy to tissue of a patient at a surgicalsite; at least one sensor configured to detect energy an energy anomaly;and at least one processor communicatively coupled to the at least onesensor, and configured to: receive data from the at least one sensorthat energy is being emitted at an unintended location within thesurgical system; transmit an alert indicating that parasitic capacitivecoupling is occurring; and transmit an interrupt to the energy generatorto temporarily interrupt energy generation.

Example 2: The surgical system of Example 1, further comprising anenergy dissipating pad electrically coupled to a neutral electrode inthe energy generator, wherein the energy dissipating pad is configuredto conductively connect to the patient and dissipate energy away fromthe patient when energy is applied to the patient tissue by the surgicalinstrument.

Example 3: The surgical system of any one of Examples 1 or 2, whereinthe neutral electrode is configured to passively shunt energy away fromthe patient during a capacitive coupling event.

Example 4: The surgical system of any one of Examples 1-3, wherein thesurgical instrument comprises: an end effector comprising a pair ofjaws; and a shaft electrically coupled to the end effector andconfigured to deliver energy to the end effector from the energygenerator.

Example 5: The surgical system Example 4, wherein the jaws compriserounded tips configured to reduce peak voltage spikes as the jaws comeinto contact with tissue of the patient.

Example 6: The surgical system of Example 4, wherein the shaft comprisesinterrupting insulator elements configured to prevent capacitivecoupling from transmitting long distance within the shaft.

Example 7: The surgical system of Example 4, wherein the surgicalinstrument comprises a triangular one-sided blade with a thin standingupper blade element configured to reduce inductive energy transmissionbeyond the upper blade element.

Example 8: The surgical system of Example 4, wherein the end effectorcomprises one or more electrodes located on the inside portion of thejaws and configured to channel excess energy away from tissue of thepatient.

Example 9: A method of a surgical system for detecting parasiticcapacitive coupling, the surgical system comprising an energy generator,a surgical instrument, and at least one sensor for detecting an energyanomaly, the method comprising: receiving data from the at least onesensor that energy is being emitted at an unintended location within thesurgical system; transmitting an alert indicating that parasiticcapacitive coupling is occurring; and transmitting an interrupt to theenergy generator to temporarily interrupt energy generation.

Example 10: A surgical instrument configured to mitigate parasiticcapacitive coupling during surgery, comprising: an electrical inputconfigured to be electrically coupled to an energy generator, a shaft;an end effector at a distal end of the shaft; at least one sensorconfigured to detect energy an energy anomaly; and at least oneprocessor communicatively coupled to the at least one sensor, andconfigured to: receive data from the at least one sensor that energy isbeing emitted at an unintended location within the surgical system;transmit an alert indicating that parasitic capacitive coupling isoccurring; and transmit an interrupt to the energy generator totemporarily interrupt energy generation.

Example 11: The surgical instrument of Example 10, wherein the endeffector comprises a pair of jaws, and the jaws comprise rounded tipsconfigured to reduce peak voltage spikes as the jaws come into contactwith tissue of the patient.

Example 12: The surgical instrument of Example 10 or 11, wherein theshaft comprises interrupting insulator elements configured to preventcapacitive coupling from transmitting long distance within the shaft.

Example 13: The surgical instrument of any one of Examples 10-12,furthering comprising a triangular one-sided blade with a thin standingupper blade element configured to reduce inductive energy transmissionbeyond the upper blade element.

Example 14: The surgical instrument of any one of Examples 10-13,wherein the end effector comprises one or more electrodes located on aninside portion of the jaws and configured to channel excess energy awayfrom tissue of the patient.

Various additional aspects of the subject matter described herein areset out in the following numbered examples.

Example 1: A surgical system comprising: a monopolar energy generator, asurgical instrument electrically coupled to the monopolar energygenerator comprising an electrode and configured to transmitelectrosurgical energy through the electrode to tissue of a patient at asurgical site; at least one detection circuit configured to: measure anamount of conductivity in a return path of the electrosurgical energy;determine that the amount conductivity in the return path falls below apredetermined threshold; and transmit a signal to cause the monopolargenerator to increase current leakage in the surgical system byincreasing alternating current frequency in the electrosurgical energygeneration; wherein the monopolar energy generator comprises a sensorconfigured to determine that a monopolar energy circuit is completed bydetecting that the current leakage has reached a ground terminal in themonopolar energy generator.

Example 2: The surgical system of Example 1, wherein increasing thecurrent leakage allows for monopolar electrosurgery of the patient to beperformed using the surgical instrument.

Example 3: The surgical system of Example 1 or 2, wherein the monopolarenergy generator further comprises a control circuit configured to:receive an indication from the sensor that the current leakage has notyet reached the ground terminal in the monopolar energy generator, andin response to the indication, further increase the alternating currentfrequency.

Example 4: The surgical system of Example 3, wherein the control circuitis further configured to: receive a second indication from the sensorthat, in response to further increasing the alternating currentfrequency, the current leakage has reached the ground terminal in themonopolar energy generator, and in response to the second indication,cease increasing the alternating current frequency.

Example 5: The surgical system of any one of Examples 1-4, wherein thesurgical system is further configured to provide an instruction toisolate any return path pads away from the surgical system to minimizeconductivity flowing through any of the return path pads.

Example 6: The surgical system of any one of Examples 1-5, whereinincreasing the frequency comprises increasing the frequency to a rangeof 500 KHz to 4 MHz.

Example 7: A monopolar energy generator of a surgical system coupled toa surgical instrument configured to transmit electrosurgical energy totissue of a patient at a surgical site, the energy generator comprising:a power supply configured to generator monopolar electrosurgical energy;a completion circuit sensor, a control circuit; and a ground terminal;wherein the control circuit is configured to: receive a signal from adetection circuit that an amount of conductivity in a return path of themonopolar electrosurgical energy falls below a predetermined threshold;and in response to the signal; cause the power supply to increasecurrent leakage by increasing alternating current frequency; wherein thecompletion circuit sensor is configured to determine that a monopolarenergy circuit is completed by detecting that the current leakage hasreached the ground terminal.

Example 8: The monopolar energy generator of Example 7, whereinincreasing the current leakage allows for monopolar electrosurgery ofthe patient to be performed using the surgical instrument.

Example 9: The monopolar energy generator of Example 7 or 8, wherein thecontrol circuit is further configured to: receive an indication from thecompletion circuit sensor that the current leakage has not yet reachedthe ground terminal; and in response to the indication, further increasethe alternating current frequency.

Example 10: The monopolar energy generator of Example 9, wherein thecontrol circuit is further configured to: receive a second indicationfrom the sensor that, in response to further increasing the alternatingcurrent frequency, the current leakage has reached the ground terminalin the monopolar energy generator, and in response to the secondindication, cease increasing the alternating current frequency.

Example 11: The monopolar energy generator of any one of Examples 7-10,further configured to provide an instruction to isolate any return pathpads away from the surgical system to minimize conductivity flowingthrough any of the return path pads.

Example 12: The monopolar energy generator of any one of Examples 7-10,wherein increasing the frequency comprises increasing the frequency to arange of 500 KHz to 4 MHz.

Example 13: A closed loop method of a surgical system, the surgicalsystem comprising a monopolar energy generator, a surgical instrumentcoupled to the energy generator, and a detection circuit communicativelycoupled to the energy generator, the method comprising: generating, bythe energy generator, electrosurgical energy to the surgical instrument;transmitting, by the surgical instrument, electrosurgical energy througha electrode to tissue of a patient at a surgical site; measuring, by thedetection circuit, an amount of conductivity in a return path of theelectrosurgical energy; determining, by the detection circuit, that theamount conductivity in the return path falls below a predeterminedthreshold; transmitting, by the detection circuit, a signal to themonopolar energy generator to cause the energy generator to increasecurrent leakage in the surgical system by increasing alternating currentfrequency in the electrosurgical energy generation; and determining, bya sensor in the monopolar energy generator, that a monopolar energycircuit is completed by detecting that the current leakage has reached aground terminal in the monopolar energy generator.

Example 14: The method of Example 13, wherein increasing the currentleakage allows for monopolar electrosurgery of the patient to beperformed using the surgical instrument.

Example 15: The method of Example 13 or 14, further comprising:receiving an indication from the sensor that the current leakage has notyet reached the ground terminal in the monopolar energy generator, andin response to the indication, further increasing the alternatingcurrent frequency.

Example 16: The method of Example 15, further comprising: receiving asecond indication from the sensor that, in response to furtherincreasing the alternating current frequency, the current leakage hasreached the ground terminal in the monopolar energy generator, and inresponse to the second indication, ceasing increasing the alternatingcurrent frequency.

Example 17: The method of anyone of Examples 13-16, further comprisingproviding an instruction to isolate any return path pads away from thesurgical system to minimize conductivity flowing through any of thereturn path pads.

Example 18: The method of any one of Examples 13-17, wherein increasingthe frequency comprises increasing the frequency to a range of 500 KHzto 4 MHz.

Various additional aspects of the subject matter described herein areset out in the following examples.

Example 1: A method of adjusting a compression force applied by asurgical instrument, wherein the surgical instrument comprises an endeffector and a clamp arm configured to receive energy modalities from agenerator configured to deliver a plurality of energy modalities to thesurgical instrument. The method comprises determining, by a controlcircuit, tissue impedance of tissue in contact with an end effector ofthe surgical instrument; determining, by the control circuit, a tissuetype based on the tissue impedance; selecting, by the control circuit, afirst energy modality of the plurality of energy modalities to deliverto the surgical instrument; generating, by the control circuit, a firstsignal waveform based on the first energy modality; selecting, by thecontrol circuit, a second energy modality of the plurality of energymodalities to deliver to the surgical instrument; generating, by thecontrol circuit, a second signal waveform based on the second energymodality; outputting, by the generator, the first and second signalwaveform to deliver energy to the end effector, and adjusting, by thecontrol circuit, a compression force applied by the end effector bychanging a size of a gap between the tissue and the clamp arm based on aproportion of the first signal waveform to the second signal waveform.

Example 2: The method of Example 1, wherein the first energy modality isa radio frequency (RF) energy modality and the second energy modality isan ultrasonic energy modality.

Example 3: The method of Example 1 or 2, wherein determining the tissueimpedance comprises: applying, by the generator, a non-therapeuticelectrical signal to the end effector over a range of frequencies; anddetermining, by the control circuit, an impedance characteristic patternbased on spectral analysis of the non-therapeutic electrical signal.

Example 4: The method of any one of Examples 1-3, wherein the proportionis determined by the control circuit based on a time that each of thefirst and second signal waveform is applied during a surgical treatmentcycle or amplitude of each of the first and second signal waveform or acombination thereof.

Example 5: The method of any one of Examples 1-4, wherein adjusting thecompression force comprises actuating a mechanical switch coupled to theclamp arm, wherein a first position of the mechanical switch correspondsto a first actuation of the clamp arm resulting in high compressionforce, and wherein a second position of the mechanical switchcorresponds to a second actuation of the clamp arm resulting in lowcompression force.

Example 6: The method of any one of Examples 1-5, wherein adjusting thecompression force comprises expanding an electroactive polymer coupledto the clamp arm, and wherein expanding the electroactive polymer basedon applying the first and second signal waveform to the end effector.

Example 7: A surgical instrument comprises a control circuit. Thecontrol circuit is configured to communicatively couple to a generatorconfigured to deliver a plurality of energy modalities to an endeffector of the surgical instrument, wherein the control circuit isfurther configured to: determine tissue impedance of tissue in contactwith an end effector of the surgical instrument; determine a tissue typeof based on the tissue impedance; select a first energy modality of theplurality of energy modalities; generate a first signal waveform basedon the first energy modality; select a second energy modality of theplurality of energy modalities; generate a second signal waveform basedon the second energy modality; and adjust a compression force applied byan end effector to tissue by changing a gap between tissue and an endeffector based on a proportion of the first signal waveform to thesecond signal waveform.

Example 8: The surgical instrument of Example 7, further comprising anend effector coupled to the control circuit, wherein the end effectorcomprises a clamp arm and an ultrasonic blade.

Example 9: The surgical instrument of Example 7 or 8, further comprisinga generator coupled to the control circuit.

Example 10: The surgical instrument of any one of Examples 7-10, whereinthe control circuit determines proportion based on a time that each ofthe first and second signal waveform are applied during a surgicaltreatment cycle or amplitude of each of the first and second signalwaveform or a combination thereof.

Example 11: The surgical instrument of any one of Examples 7-10, whereinthe control circuit adjusts the compression force based on actuating amechanical switch coupled to the clamp arm, wherein a first position ofthe mechanical switch corresponds to a first actuation of the clamp armresulting in high compression force, and wherein a second position ofthe mechanical switch corresponds to a second actuation of the clamp armresulting in low compression force.

Example 12: The surgical instrument of any one of Examples 7-11, whereinthe control circuit adjusts the compression force based on expansion ofan electroactive polymer coupled to the clamp arm, and wherein theelectroactive polymer expands based on applying the first and secondsignal waveform to the end effector.

Example 13: A surgical system comprises a surgical hub configured toreceive a tissue treatment algorithm transmitted from a cloud computingsystem, wherein the surgical hub is communicatively coupled to the cloudcomputing system; and a surgical instrument communicatively coupled tothe surgical hub, wherein the surgical instrument comprises: an endeffector comprising: a clamp arm; and a ultrasonic blade; a generatorconfigured to deliver a plurality of energy modalities to the endeffector, a control circuit communicatively coupled to the end effectorand the generator, wherein the control circuit is configured to treattissue, and wherein the control circuit is configured to: determinetissue impedance of tissue in contact with the end effector, determinetissue type based on the tissue impedance; select a first energymodality of the plurality of energy modalities; generate a first signalwaveform based on the first energy modality; select a second energymodality of the plurality of energy modalities; generate a second signalwaveform based on the second energy modality; apply the first and secondsignal waveform to the end effector, and adjust a compression forceapplied by the end effector by changing a size of a gap between thetissue and the waveguide based on a proportion of the first signalwaveform to the second signal waveform.

Example 14: The surgical instrument of Example 13, wherein the firstenergy modality is a radio frequency (RF) energy modality and the secondenergy modality is an ultrasonic energy modality.

Example 15: The surgical instrument of Example 13 or 14, wherein todetermine the tissue impedance, the control circuit is configured: applya non-therapeutic electrical signal to the end effector over a range offrequencies; and determine an impedance characteristic pattern based onspectral analysis of the non-therapeutic electrical signal.

Example 16: The surgical instrument of any one of Examples 13-15,wherein the control circuit determines the proportion based on a timethat each of the first and second signal waveform are applied during asurgical treatment cycle or an amplitude of each of the first and secondsignal waveform or a combination thereof.

Example 17: The surgical instrument of any one of Examples 13-16,wherein to adjust the compression force, the control circuit isconfigured to actuate a mechanical switch coupled to the clamp arm,wherein a first position of the mechanical switch corresponds to a firstactuation of the clamp arm resulting in high compression force, andwherein a second position of the mechanical switch corresponds to asecond actuation of the clamp arm resulting in low compression force.

Example 18: The surgical instrument of any one of Examples 13-17,wherein to adjust the compression force, the control circuit isconfigured to expand an electroactive polymer coupled to the clamp arm,and to expand the electroactive polymer based on the first and secondsignal waveforms applied to the end effector.

Example 19: The surgical instrument of any one of Examples 14-18,wherein the RF energy modality corresponds to a first range ofcompression force and the ultrasonic energy modality to a second rangeof compression force, and wherein the first range of compression forceis greater than the second range of compression force.

Example 20: The surgical instrument of any one of Examples 13-19,wherein the surgical instrument comprises a passive electrode and anactive electrode.

Various additional aspects of the subject matter described herein areset out in the following numbered examples.

Example 1: An electrosurgical device, comprising: a controllercomprising an electrical generator, a surgical probe comprising a distalactive electrode, wherein the active electrode is in electricalcommunication with an electrical source terminal of the electricalgenerator, and a return pad in electrical communication with anelectrical return terminal of the electrical generator, wherein theelectrical generator is configured to source an electrical current fromthe electrical source terminal, and wherein the electrical currentsourced by the electrical generator combines characteristics of atherapeutic electrical signal and characteristics of an excitable tissuestimulating signal.

Example 2: The electrosurgical device of Example 1, wherein thetherapeutic electrical signal is a radiofrequency signal having afrequency greater than 200 kHz and less than 5 MHz.

Example 3:The electrosurgical device of any one or more of Examples 1through 2, wherein the excitable tissue stimulating signal is an ACsignal having a frequency less than 200 kHz.

Example 4: The electrosurgical device of any one or more of Examples 1through 3, wherein the electrical current sourced by the electricalgenerator comprises at least one alternating therapeutic electricalsignal and at least one alternating excitable tissue stimulating signal.

Example 5: The electrosurgical device of any one or more of Examples 1through 4, wherein the electrical current sourced by the electricalgenerator comprises a therapeutic electrical signal amplitude modulatedby the excitable tissue stimulating signal.

Example 6: The electrosurgical device of any one or more of Examples 1through 5, wherein the electrical current sourced by the electricalgenerator comprises a therapeutic electrical signal DC offset by theexcitable tissue stimulating signal.

Example 7: The electrosurgical device of any one or more of Examples 1through 6, wherein the return pad further comprises at least one sensingdevice having a sensing device output, and the sensing device isconfigured to determine a stimulation of an excitable tissue by theexcitable tissue stimulating signal.

Example 8: The electrosurgical device of Example 7, wherein thecontroller is configured to receive the sensing device output.

Example 9: The electrosurgical device of Example 8, wherein thecontroller comprises a processor and at least one memory component indata communication with the processor, and wherein the at least onememory component stores one or more instructions that, when executed bythe processor, cause the processor to determine a distance of the activeelectrode from an excitable tissue based at least in part on the sensoroutput received by the controller.

Example 10: The electrosurgical device of Example 9, wherein the atleast one memory component stores one or more instructions that, whenexecuted by the processor, cause the processor to alter a value of atleast one characteristic of the therapeutic electrical signal when thedistance of the active electrode from an excitable tissue is less than apredetermined value.

Example 11: An electrosurgical system comprising: a processor, and amemory coupled to the processor, the memory configured to storeinstructions executable by the processor to: cause an electricalgenerator to combine one or more characteristics of a therapeutic signalwith one or more characteristics of an excitable tissue stimulatingsignal to form a combination signal; cause the electrical generator totransmit the combination signal into a tissue of a patient through anactive electrode in physical contact with the patient; and receive asensing device output signal from a sensing device disposed within areturn pad in physical contact with the patient.

Example 12: The electrosurgical system of Example 11, wherein the memoryis configured to further store instructions executable by the processorto: determine, based at least in part on the sensing device outputsignal, a distance from the active electrode to an excitable tissue.

Example 13: The electrosurgical system of Example 12, wherein the memoryis configured to further store instructions executable by the processorto: cause the controller to alter one or more characteristics of thetherapeutic signal when the distance from the active electrode to theexcitable tissue is less than a predetermined value.

Example 14: The electrosurgical system of any one or more of Examples11-13, wherein the instructions executable by the processor to cause anelectrical generator to combine one or more characteristics of atherapeutic signal with one or more characteristics of an excitabletissue stimulating signal to form a combination signal comprisesinstructions executable by the processor to cause the electricalgenerator to alternate the therapeutic signal and the excitable tissuestimulating signal.

Example 15: The electrosurgical system of any one or more of Examples11-14, wherein the instructions executable by the processor to cause anelectrical generator to combine one or more characteristics of atherapeutic signal with one or more characteristics of an excitabletissue stimulating signal to form a combination signal comprisesinstructions executable by the processor to cause the electricalgenerator to modulate an amplitude of the therapeutic signal by anamplitude of the excitable tissue stimulating signal.

Example 16: The electrosurgical system of any one or more of Examples11-15, wherein the instructions executable by the processor to cause anelectrical generator to combine one or more characteristics of atherapeutic signal with one or more characteristics of an excitabletissue stimulating signal to form a combination signal comprisesinstructions executable by the processor to cause the electricalgenerator to offset a DC value of the therapeutic signal by an amplitudeof the excitable tissue stimulating signal.

Example 17: An electrosurgical system comprising: a control circuitconfigured to: control an electrical output of an electrical generator,in which the electrical output comprises one or more characteristics ofa therapeutic signal and one or more characteristics of an excitabletissue stimulating signal; receive a sensing device signal from at leastone sensing device configured to measure an activity of an excitabletissue of a patient; determine a distance between a location of anactive electrode configured to transmit the electrical output of theelectrical generator into a patient tissue and a location of the atleast one sensing device; and alter the electrical output of theelectrical generator in at least one characteristic of the therapeuticsignal when the distance between the location of the active electrodeconfigured to transmit the electrical output of the electrical generatorinto the patient tissue and the location of the at least one sensingdevice is less than a pre-determined value.

Example 18: The electrosurgical system of Example 17, wherein thecontrol circuit configured to alter the electrical output of theelectrical generator in at least one characteristic of the therapeuticsignal when the distance between the location of the active electrodeconfigured to transmit the electrical output of the electrical generatorinto the patient tissue and the location of the at least one sensingdevice is less than a pre-determined value comprises a control circuitconfigured to minimize the at least one characteristic of thetherapeutic signal.

Example 19: A non-transitory computer readable medium storing computerreadable instructions which, when executed, causes a machine to: controlan electrical output of an electrical generator, in which the electricaloutput comprises one or more characteristics of a therapeutic signal andone or more characteristics of an excitable tissue stimulating signal;receive a sensing device signal from at least one sensing deviceconfigured to measure an activity of an excitable tissue of a patient;determine a distance between a location of an active electrodeconfigured to transmit the electrical output of the electrical generatorinto a patient tissue and a location of the at least one sensing device;and alter the electrical output of the electrical generator in at leastone characteristic of the therapeutic signal when the distance betweenthe location of the active electrode configured to transmit theelectrical output of the electrical generator into the patient tissueand the location of the at least one sensing device is less than apre-determined value.

Various additional aspects of the subject matter described herein areset out in the following numbered examples:

Example 1: A surgical instrument comprising: an ultrasonic blade, an armpivotable relative to the ultrasonic blade between an open position anda closed position, a transducer assembly coupled to the ultrasonicblade, a sensor configured to sense a position of the arm between theopen position and the closed position, and a control circuit coupled tothe transducer assembly and the sensor. The transducer assemblycomprises at least two piezoelectric elements configured toultrasonically oscillate the ultrasonic blade. The control circuit isconfigured to activate the transducer assembly according to a positionof the arm detected by the sensor relative to a threshold position.

Example 2: The surgical instrument of Example 1, wherein the sensorcomprises a Hall effect sensor.

Example 3: The surgical instrument of Example 2, wherein the armcomprises a magnet detectable by the Hall effect sensor.

Example 4: The surgical instrument of Example 2, wherein the Hall effectsensor is configured to detect a magnet disposed on a user.

Example 5: The surgical instrument of any one of Examples 1-4, whereinthe threshold position corresponds to the open position.

Example 6: The surgical instrument of any one of Examples 1-5, whereinthe threshold position corresponds to the closed position.

Example 7: A surgical instrument comprising: an ultrasonic blade, an armpivotable relative to the ultrasonic blade between an open position anda closed position, a transducer assembly coupled to the ultrasonicblade, a first sensor configured to sense a first force as the armtransitions to the closed position, a second sensor configured to sensea second force as the arm transitions to the open position, and acontrol circuit coupled to the transducer assembly, the first sensor,and the second sensor. The transducer assembly comprises at least twopiezoelectric elements configured to ultrasonically oscillate theultrasonic blade. The control circuit is configured to activate thetransducer assembly according to the first force sensed by the firstsensor relative to a first threshold and the second force sensed by thesecond sensor relative to a second threshold.

Example 8: The surgical instrument of Example 7, wherein the firstsensor comprise a tactile switch.

Example 9: The surgical instrument of Example 8, wherein the tactileswitch comprises a two-stage tactile switch.

Example 10: The surgical instrument of Example 9, wherein the firstthreshold correspond to a second stage of the two-stage tactile switch.

Example 11: The surgical instrument of any one of Examples 7-10, whereinthe first sensor is disposed on a housing of the surgical instrumentsuch that the arm bears thereagainst as the arm transitions to theclosed position.

Example 12: The surgical instrument of any one of Examples 7-11, whereinthe second sensor comprise a tactile switch.

Example 13: The surgical instrument of Example 12, wherein the tactileswitch comprises a one-stage tactile switch.

Example 14: The surgical instrument of any one of Examples 7-13, whereinthe second threshold correspond to a non-zero force.

Example 15: The surgical instrument of any one of Examples 7-14, whereinthe second sensor is disposed adjacent to a rotation point between thearm and the ultrasonic blade such that the arm bears against the secondsensor as the arm transitions to the open position.

Example 16: A surgical instrument comprising: an ultrasonic blade, atransducer assembly coupled to the ultrasonic blade, a sensor configuredto sense a force thereagainst, and a control circuit coupled to thetransducer assembly and the sensor. The transducer assembly comprises atleast two piezoelectric elements configured to ultrasonically oscillatethe ultrasonic blade. The control circuit is configured to activate thetransducer assembly according to the force sensed by the sensor relativeto a threshold force.

Example 17: The surgical instrument of Example 16, wherein the sensorcomprises a force sensitive resistor.

Example 18: The surgical instrument of Example 16 or 17, wherein thecontrol circuit is configured to activate the transducer assembly whenthe force sensed by the sensor exceeds the threshold force.

Example 19: The surgical instrument of any one of Examples 16-18,wherein the sensor is disposed on an exterior surface of the surgicalinstrument.

Example 20: The surgical instrument of any one of Examples 16-19,wherein an output of the sensor varies according to a degree of forcethereagainst and the control circuit is configured to activate thetransducer assembly according to the output of the sensor relative to athreshold representative of the threshold force.

Various additional aspects of the subject matter described herein areset out in the following numbered examples

Example 1: A method of estimating a state of an end effector of anultrasonic device, the ultrasonic device including an electromechanicalultrasonic system defined by a predetermined resonant frequency, theelectromechanical ultrasonic system including an ultrasonic transducercoupled to an ultrasonic blade, the method comprising: measuring, by acontrol circuit, a complex impedance of an ultrasonic transducer,wherein the complex impedance is defined as

${{Z_{g}(t)} = \frac{V_{g}(t)}{I_{g}(t)}};$

receiving, by the control circuit, a complex impedance measurement datapoint; comparing, by the control circuit, the complex impedancemeasurement data point to a data point in a reference complex impedancecharacteristic pattern; classifying, by the control circuit, the compleximpedance measurement data point based on a result of the comparisonanalysis; and assigning, by the control circuit, a state or condition ofthe end effector based on the result of the comparison analysis.

Example 2: The method of Example 1, comprising: receiving, by thecontrol circuit, the reference complex impedance characteristic patternfrom a database or memory coupled to the control circuit; andgenerating, by the control circuit, the reference complex impedancecharacteristic pattern as follows: applying, by a drive circuit coupledto the control circuit, a nontherapeutic drive signal to the ultrasonictransducer starting at an initial frequency, ending at a finalfrequency, and at a plurality of frequencies therebetween; measuring, bythe control circuit, the impedance of the ultrasonic transducer at eachfrequency; storing, by the control circuit, a data point correspondingto each impedance measurement; and curve fitting, by the controlcircuit, a plurality of data points to generate a three-dimensionalcurve of representative of the reference complex impedancecharacteristic pattern, wherein the magnitude |Z| and phase φ areplotted as a function of frequency f.

Example 3: The method of Example 2, where the curve fitting includes apolynomial curve fit, a Fourier series, and/or a parametric equation.

Example 4: The method of any one of Examples 1-3, comprising: receiving,by the control circuit, a new impedance measurement data point; andclassifying, by the control circuit, the new impedance measurement datapoint using a Euclidean perpendicular distance from the new impedancemeasurement data point to a trajectory which has been fitted to thereference complex impedance characteristic pattern.

Example 5: The method of Example 4, comprising estimating, by thecontrol circuit, a probability that the new impedance measurement datapoint is correctly classified.

Example 6: The method of Example 5, comprising adding, by the controlcircuit, the new impedance measurement data point to the referencecomplex impedance characteristic pattern based on the probability of theestimated correct classification of the new impedance measurement datapoint.

Example 7: The method of Example 4, comprising: classifying by thecontrol circuit, data based on a set of training data S, where the setof training data S comprises a plurality of complex impedancemeasurement data; curve fitting, by the control circuit, the set oftraining data S using a parametric Fourier series; wherein S is definedby:

$\overset{\rightharpoonup}{p} = {{\overset{\rightharpoonup}{a}}_{0} + {\sum\limits_{n = 1}^{\infty}\left( {{{\overset{\rightharpoonup}{a}}_{n}\cos\frac{n\pi t}{L}} + {{\overset{\rightharpoonup}{b}}_{n}\sin\frac{n\pi t}{L}}} \right)}}$

wherein, for a new impedance measurement data point

, a perpendicular distance from

to

is found by:

D=∥

−

∥

when:

$\frac{\partial D}{\partial t} = 0$then:

D=D _(⊥)

wherein the probability distribution of D is used to estimate theprobability of the new impedance measurement data point

belonging to the group S.

Example 8: The method of claim 1, wherein the control circuit is locatedat a surgical hub in communication with the ultrasonic electromechanicalsystem.

Example 9: A generator for estimating a state of an end effector of anultrasonic device, the ultrasonic device including an electromechanicalultrasonic system defined by a predetermined resonant frequency, theelectromechanical ultrasonic system including an ultrasonic transducercoupled to an ultrasonic blade, the generator comprising: a controlcircuit coupled to a memory, the control circuit configured to: measurea complex impedance of an ultrasonic transducer, wherein the compleximpedance is defined as

${{Z_{g}(t)} = \frac{V_{g}(t)}{I_{g}(t)}};$

receive a complex impedance measurement data point; compare the compleximpedance measurement data point to a data point in a reference compleximpedance characteristic pattern; classify the complex impedancemeasurement data point based on a result of the comparison analysis; andassign a state or condition of the end effector based on the result ofthe comparison analysis.

Example 10: The generator of Example 9, further comprising: a drivecircuit coupled to the control circuit, the drive circuit configured toapply a nontherapeutic drive signal to the ultrasonic transducerstarting at an initial frequency, ending at a final frequency, and at aplurality of frequencies therebetween; wherein the control circuit isfurther configured to generate the reference complex impedancecharacteristic pattern; wherein the control circuit is configured toreceive the reference complex impedance characteristic pattern from adatabase or the memory coupled to the control circuit; measure theimpedance of the ultrasonic transducer at each frequency; store in thememory a data point corresponding to each impedance measurement; andcurve fit a plurality of data points to generate a three-dimensionalcurve of representative of the reference complex impedancecharacteristic pattern, wherein the magnitude |Z| and phase φ areplotted as a function of frequency f.

Example 11: The generator of any one of Example 10, wherein the curvefit includes a polynomial curve fit, a Fourier series, and/or aparametric equation.

Example 12: The generator of any one of Examples 9-11, wherein thecontrol circuit is further configured to: receive a new impedancemeasurement data point; and classify the new impedance measurement datapoint using a Euclidean perpendicular distance from the new impedancemeasurement data point to a trajectory which has been fitted to thereference complex impedance characteristic pattern.

Example 13: The generator of Example 11, wherein the control circuit isfurther configured to estimate a probability that the new impedancemeasurement data point is correctly classified.

Example 14: The generator of Example 13, wherein the control circuit isfurther configured to add the new impedance measurement data point tothe reference complex impedance characteristic pattern based on theprobability of the estimated correct classification of the new impedancemeasurement data point.

Example 15: The generator of Example 13, wherein the control circuit isfurther configured to: classify data based on a set of training data S,where the set of training data S comprises a plurality of compleximpedance measurement data; curve fit the set of training data S using aparametric Fourier series; wherein S is defined by:

$\overset{\rightharpoonup}{p} = {{\overset{\rightharpoonup}{a}}_{0} + {\sum\limits_{n = 1}^{\infty}\left( {{{\overset{\rightharpoonup}{a}}_{n}\cos\frac{n\pi t}{L}} + {{\overset{\rightharpoonup}{b}}_{n}\sin\frac{n\pi t}{L}}} \right)}}$

wherein, for a new impedance measurement data point

, a perpendicular distance from

to

is found by:

D=∥

−

∥

when:

$\frac{\partial D}{\partial t} = 0$then:

D=D _(⊥)

wherein the probability distribution of D is used to estimate theprobability of the new impedance measurement data point

to the group S.

Example 16: The generator of claim 9, wherein the control circuit andthe memory are located at a surgical hub in communication with theultrasonic electromechanical system.

Example 17: An ultrasonic device for estimating a state of an endeffector thereof, the ultrasonic device comprising: an electromechanicalultrasonic system defined by a predetermined resonant frequency, theelectromechanical ultrasonic system comprising an ultrasonic transducercoupled to an ultrasonic blade; a control circuit coupled to a memory,the control circuit configured to: measure a complex impedance of theultrasonic transducer, wherein the complex impedance is defined as

${{Z_{g}(t)} = \frac{V_{g}(t)}{I_{g}(t)}};$

receive a complex impedance measurement data point; compare the compleximpedance measurement data point to a data point in a reference compleximpedance characteristic pattern; classify the complex impedancemeasurement data point based on a result of the comparison analysis; andassign a state or condition of the end effector based on the result ofthe comparison analysis.

Example 18: The ultrasonic device of Example 17, further comprising: adrive circuit coupled to the control circuit, the drive circuitconfigured to apply a nontherapeutic drive signal to the ultrasonictransducer starting at an initial frequency, ending at a finalfrequency, and at a plurality of frequencies therebetween; wherein thecontrol circuit is further configured to generate the reference compleximpedance characteristic pattern; wherein the control circuit isconfigured to receive the reference complex impedance characteristicpattern from a database or the memory coupled to the control circuit;measure the impedance of the ultrasonic transducer at each frequency;store in the memory a data point corresponding to each impedancemeasurement; and curve fit a plurality of data points to generate athree-dimensional curve of representative of the reference compleximpedance characteristic pattern, wherein the magnitude |Z| and phase φare plotted as a function of frequency f.

Example 19: The ultrasonic device of Example 18, wherein the curve fitincludes a polynomial curve fit, a Fourier series, and/or a parametricequation.

Example 20: The ultrasonic device of any one of Examples 17-19, whereinthe control circuit is further configured to: receive a new impedancemeasurement data point; and classify the new impedance measurement datapoint using a Euclidean perpendicular distance from the new impedancemeasurement data point to a trajectory which has been fitted to thereference complex impedance characteristic pattern.

Example 21: The ultrasonic device of Example 20, wherein the controlcircuit is further configured to estimate a probability that the newimpedance measurement data point is correctly classified.

Example 22: The ultrasonic device of Example 21, wherein the controlcircuit is further configured to add the new impedance measurement datapoint to the reference complex impedance characteristic pattern based onthe probability of the estimated correct classification of the newimpedance measurement data point.

Example 23: The ultrasonic device of Example 21, wherein the controlcircuit is further configured to: classify data based on a set oftraining data S, where the set of training data S comprises a pluralityof complex impedance measurement data; curve fit the set of trainingdata S using a parametric Fourier series; wherein S is defined by:

$\overset{\rightharpoonup}{p} = {{\overset{\rightharpoonup}{a}}_{0} + {\sum\limits_{n = 1}^{\infty}\left( {{{\overset{\rightharpoonup}{a}}_{n}\cos\frac{n\pi t}{L}} + {{\overset{\rightharpoonup}{b}}_{n}\sin\frac{n\pi t}{L}}} \right)}}$

wherein, for a new impedance measurement data point

, a perpendicular distance from

to

is found by:

D=∥

−

∥

when:

$\frac{\partial D}{\partial t} = 0$

then:

D=D _(⊥)

wherein the probability distribution of D is used to estimate theprobability of the new impedance measurement data point

belonging to the group S.

Example 24: The ultrasonic device of any one of Examples 17-23, whereinthe control circuit and the memory are located at a surgical hub incommunication with the ultrasonic electromechanical system.

Example 25: A method of estimating a state of an end effector of anultrasonic device, the ultrasonic device including an electromechanicalultrasonic system defined by a predetermined resonant frequency, theelectromechanical ultrasonic system including an ultrasonic transducercoupled to an ultrasonic blade, the method comprising: applying, by adrive circuit, a drive signal to an ultrasonic transducer, wherein thedrive signal is a periodic signal defined by a magnitude and frequency;sweeping, by a processor or control circuit, the frequency of the drivesignal from below resonance to above resonance of the electromagneticultrasonic system; measuring and recording, by the processor or controlcircuit, impedance/admittance circle variables R_(e), G_(e), X_(e),B_(e); comparing, by the processor or control circuit, measuredimpedance/admittance circle variables R_(e), G_(e), X_(e), B_(e) toreference impedance/admittance circle variables Rr, G_(ref), X_(ref),B_(ref); and determining, by the processor or control circuit, a stateor condition of the end effector based on the result of the comparisonanalysis.

Various aspects of the subject matter described herein are set out inthe following numbered examples:

Example 1: A method of determining a temperature of an ultrasonic blade,the method comprising: determining, by a control circuit coupled to amemory, an actual resonant frequency of an ultrasonic electromechanicalsystem comprising an ultrasonic transducer coupled to an ultrasonicblade by an ultrasonic waveguide, wherein the actual resonant frequencyis correlated to an actual temperature of the ultrasonic blade;retrieving, from the memory by the control circuit, a reference resonantfrequency of the ultrasonic electromechanical system, wherein thereference resonant frequency is correlated to a reference temperature ofthe ultrasonic blade; and inferring, by the control circuit, thetemperature of the ultrasonic blade based on the difference between theactual resonant frequency and the reference resonant frequency.

Example 2: The method of Example 1, wherein determining, by the controlcircuit, the actual resonant frequency of the ultrasonicelectromechanical system comprises: determining, by the control circuit,a phase angle φ between a voltage V_(g)(t) and a current I_(g)(t) signalapplied to the ultrasonic transducer.

Example 3: The method of Example 2, further comprising generating, bythe control circuit, a temperature estimator and state space model ofthe inferred temperature of the ultrasonic blade as a function of theresonant frequency of the ultrasonic electromechanical system based on aset of non-linear state space equations.

Example 4: The method of Example 3, wherein the state space model isdefined by:

${\begin{bmatrix}\overset{.}{F_{n}} \\\overset{.}{T}\end{bmatrix} = {f\left( {t,{T(t)},{F_{n}(t)},{E(t)}} \right)}}{\overset{.}{y} = {{h\left( {t,{T(t)},{F_{n}(t)},{E(t)}} \right)}.}}$

Example 5: The method of Example 4, further comprising applying, by thecontrol circuit, a Kalman filter to improve the temperature estimatorand state space model.

Example 6: The method of Example 5, further comprising: applying, by thecontrol circuit, a state estimator in a feedback loop of the Kalmanfilter, controlling, by the control circuit, power applied to theultrasonic transducer, and regulating, by the control circuit, thetemperature of the ultrasonic blade.

Example 7: The method of Example 6, wherein a state variance of thestate estimator of the Kalman filter is defined by:

(σ_(k) ⁻)²=σ_(k-1) ²+σ_(P) _(k) ² and

a gain K of the Kalman filter is defined by:

$K = {\frac{\left( \sigma_{k}^{-} \right)^{2}}{\left( \sigma_{k}^{-} \right)^{2} + \sigma_{m}^{2}}.}$

Example 8: The method of Example 1, wherein the control circuit andmemory are located at a surgical hub in communication with theultrasonic electromechanical system.

Example 9: A generator for determining a temperature of an ultrasonicblade, the generator comprising: a control circuit coupled to a memory,the control circuit configured to: determine an actual resonantfrequency of an ultrasonic electromechanical system comprising anultrasonic transducer coupled to an ultrasonic blade by an ultrasonicwaveguide, wherein the actual resonant frequency is correlated to anactual temperature of the ultrasonic blade; retrieve from the memory areference resonant frequency of the ultrasonic electromechanical system,wherein the reference resonant frequency is correlated to a referencetemperature of the ultrasonic blade; and infer the temperature of theultrasonic blade based on the difference between the actual resonantfrequency and the reference resonant frequency.

Example 10: The generator of Example 9, wherein to determine the actualresonant frequency of the ultrasonic electromechanical system, thecontrol circuit is further configured to: determine a phase angle φbetween a voltage V_(g)(t) and a current I_(g)(t) signal applied to theultrasonic transducer.

Example 11: The generator of Example 10, wherein the control circuit isfurther configured to generate a temperature estimator and state spacemodel of the inferred temperature of the ultrasonic blade as a functionof the resonant frequency of the ultrasonic electromechanical systembased on a set of non-linear state space equations.

Example 12: The generator of Example 11, wherein the state space modelis defined by:

${\begin{bmatrix}\overset{.}{F_{n}} \\\overset{.}{T}\end{bmatrix} = {f\left( {t,{T(t)},{F_{n}(t)},{E(t)}} \right)}}{\overset{.}{y} = {{h\left( {t,{T(t)},{F_{n}(t)},{E(t)}} \right)}.}}$

Example 13: The generator of Example 12, wherein the control circuit isfurther configured to apply a Kalman filter to improve the temperatureestimator and state space model.

Example 14: The generator of Example 13, wherein the control circuit isfurther configured to: apply a state estimator in a feedback loop of theKalman filter, control power applied to the ultrasonic transducer, andregulate the temperature of the ultrasonic blade.

Example 15: The generator of Example 14, wherein a state variance of thestate estimator of the Kalman filter is defined by:

(σ_(k) ⁻)²=σ_(k-1) ²+σ_(P) _(k) ² and

a gain K of the Kalman filter is defined by:

$K = {\frac{\left( \sigma_{k}^{-} \right)^{2}}{\left( \sigma_{k}^{-} \right)^{2} + \sigma_{m}^{2}}.}$

Example 16: The generator of Example 9, wherein the control circuit andmemory are located at a surgical hub in communication with thegenerator.

Example 17: An ultrasonic device for determining a temperature of anultrasonic blade, the ultrasonic device comprising: a control circuitcoupled to a memory, the control circuit configured to: determine anactual resonant frequency of an ultrasonic electromechanical systemcomprising an ultrasonic transducer coupled to an ultrasonic blade by anultrasonic waveguide, wherein the actual resonant frequency iscorrelated to an actual temperature of the ultrasonic blade; retrievefrom the memory a reference resonant frequency of the ultrasonicelectromechanical system, wherein the reference resonant frequency iscorrelated to a reference temperature of the ultrasonic blade; and inferthe temperature of the ultrasonic blade based on the difference betweenthe actual resonant frequency and the reference resonant frequency.

Example 18: The ultrasonic device of Example 17, wherein to determinethe actual resonant frequency of the ultrasonic electromechanicalsystem, the control circuit is further configured to: determine a phaseangle φ between a voltage V_(g)(t) and a current I_(g)(t) signal appliedto the ultrasonic transducer.

Example 19: The ultrasonic device of Example 18, wherein the controlcircuit is further configured to generate a temperature estimator andstate space model of the inferred temperature of the ultrasonic blade asa function of the resonant frequency of the ultrasonic electromechanicalsystem based on a set of non-linear state space equations.

Example 20: The ultrasonic device of Example 19, wherein the state spacemodel is defined by:

${\begin{bmatrix}\overset{.}{F_{n}} \\\overset{.}{T}\end{bmatrix} = {f\left( {t,{T(t)},{F_{n}(t)},{E(t)}} \right)}}{\overset{.}{y} = {{h\left( {t,{T(t)},{F_{n}(t)},{E(t)}} \right)}.}}$

Example 21: The ultrasonic device of Example 20, wherein the controlcircuit is further configured to apply a Kalman filter to improve thetemperature estimator and state space model.

Example 22: The ultrasonic device of Example 21, wherein the controlcircuit is further configured to: apply a state estimator in a feedbackloop of the Kalman filter, control power applied to the ultrasonictransducer, and regulate the temperature of the ultrasonic blade.

Example 23: The ultrasonic device of Example 22, wherein a statevariance of the state estimator of the Kalman filter is defined by:

(σ_(k) ⁻)²=σ_(k-1) ²+σ_(P) _(k) ² and

a gain K of the Kalman filter is defined by:

$K = {\frac{\left( \sigma_{k}^{-} \right)^{2}}{\left( \sigma_{k}^{-} \right)^{2} + \sigma_{m}^{2}}.}$

Example 24: The ultrasonic instrument of Example 17, wherein the controlcircuit and memory are located at a surgical hub in communication withthe ultrasonic instrument.

While several forms have been illustrated and described, it is not theintention of the applicant to restrict or limit the scope of theappended claims to such detail. Numerous modifications, variations,changes, substitutions, combinations, and equivalents to those forms maybe implemented and will occur to those skilled in the art withoutdeparting from the scope of the present disclosure. Moreover, thestructure of each element associated with the described forms can bealternatively described as a means for providing the function performedby the element. Also, where materials are disclosed for certaincomponents, other materials may be used. It is therefore to beunderstood that the foregoing description and the appended claims areintended to cover all such modifications, combinations, and variationsas falling within the scope of the disclosed forms. The appended claimsare intended to cover all such modifications, variations, changes,substitutions, modifications, and equivalents.

The foregoing detailed description has set forth various forms of thedevices and/or processes via the use of block diagrams, flowcharts,and/or examples. Insofar as such block diagrams, flowcharts, and/orexamples contain one or more functions and/or operations, it will beunderstood by those within the art that each function and/or operationwithin such block diagrams, flowcharts, and/or examples can beimplemented, individually and/or collectively, by a wide range ofhardware, software, firmware, or virtually any combination thereof.Those skilled in the art will recognize that some aspects of the formsdisclosed herein, in whole or in part, can be equivalently implementedin integrated circuits, as one or more computer programs running on oneor more computers (e.g., as one or more programs running on one or morecomputer systems), as one or more programs running on one or moreprocessors (e.g., as one or more programs running on one or moremicroprocessors), as firmware, or as virtually any combination thereof,and that designing the circuitry and/or writing the code for thesoftware and or firmware would be well within the skill of one of skillin the art in light of this disclosure. In addition, those skilled inthe art will appreciate that the mechanisms of the subject matterdescribed herein are capable of being distributed as one or more programproducts in a variety of forms, and that an illustrative form of thesubject matter described herein applies regardless of the particulartype of signal bearing medium used to actually carry out thedistribution.

Instructions used to program logic to perform various disclosed aspectscan be stored within a memory in the system, such as dynamic randomaccess memory (DRAM), cache, flash memory, or other storage.Furthermore, the instructions can be distributed via a network or by wayof other computer readable media. Thus a machine-readable medium mayinclude any mechanism for storing or transmitting information in a formreadable by a machine (e.g., a computer), but is not limited to, floppydiskettes, optical disks, compact disc, read-only memory (CD-ROMs), andmagneto-optical disks, read-only memory (ROMs), random access memory(RAM), erasable programmable read-only memory (EPROM), electricallyerasable programmable read-only memory (EEPROM), magnetic or opticalcards, flash memory, or a tangible, machine-readable storage used in thetransmission of information over the Internet via electrical, optical,acoustical or other forms of propagated signals (e.g., carrier waves,infrared signals, digital signals, etc.). Accordingly, thenon-transitory computer-readable medium includes any type of tangiblemachine-readable medium suitable for storing or transmitting electronicinstructions or information in a form readable by a machine (e.g., acomputer).

As used in any aspect herein, the term “control circuit” may refer to,for example, hardwired circuitry, programmable circuitry (e.g., acomputer processor comprising one or more individual instructionprocessing cores, processing unit, processor, microcontroller,microcontroller unit, controller, digital signal processor (DSP),programmable logic device (PLD), programmable logic array (PLA), orfield programmable gate array (FPGA)), state machine circuitry, firmwarethat stores instructions executed by programmable circuitry, and anycombination thereof. The control circuit may, collectively orindividually, be embodied as circuitry that forms part of a largersystem, for example, an integrated circuit (IC), an application-specificintegrated circuit (ASIC), a system on-chip (SoC), desktop computers,laptop computers, tablet computers, servers, smart phones, etc.Accordingly, as used herein, “control circuit” includes, but is notlimited to, electrical circuitry having at least one discrete electricalcircuit, electrical circuitry having at least one integrated circuit,electrical circuitry having at least one application specific integratedcircuit, electrical circuitry forming a general purpose computing deviceconfigured by a computer program (e.g., a general purpose computerconfigured by a computer program which at least partially carries outprocesses and/or devices described herein, or a microprocessorconfigured by a computer program which at least partially carries outprocesses and/or devices described herein), electrical circuitry forminga memory device (e.g., forms of random access memory), and/or electricalcircuitry forming a communications device (e.g., a modem, communicationsswitch, or optical-electrical equipment). Those having skill in the artwill recognize that the subject matter described herein may beimplemented in an analog or digital fashion or some combination thereof.

As used in any aspect herein, the term “logic” may refer to an app,software, firmware and/or circuitry configured to perform any of theaforementioned operations. Software may be embodied as a softwarepackage, code, instructions, instruction sets and/or data recorded onnon-transitory computer readable storage medium. Firmware may beembodied as code, instructions or instruction sets and/or data that arehard-coded (e.g., nonvolatile) in memory devices.

As used in any aspect herein, the terms “component,” “system,” “module”and the like can refer to a computer-related entity, either hardware, acombination of hardware and software, software, or software inexecution.

As used in any aspect herein, an“algorithm” refers to a self-consistentsequence of steps leading to a desired result, where a “step” refers toa manipulation of physical quantities and/or logic states which may,though need not necessarily, take the form of electrical or magneticsignals capable of being stored, transferred, combined, compared, andotherwise manipulated. It is common usage to refer to these signals asbits, values, elements, symbols, characters, terms, numbers, or thelike. These and similar terms may be associated with the appropriatephysical quantities and are merely convenient labels applied to thesequantities and/or states.

A network may include a packet switched network. The communicationdevices may be capable of communicating with each other using a selectedpacket switched network communications protocol. One examplecommunications protocol may include an Ethernet communications protocolwhich may be capable permitting communication using a TransmissionControl Protocol/Internet Protocol (TCP/IP). The Ethernet protocol maycomply or be compatible with the Ethernet standard published by theInstitute of Electrical and Electronics Engineers (IEEE) titled “IEEE802.3 Standard”, published in December, 2008 and/or later versions ofthis standard. Alternatively or additionally, the communication devicesmay be capable of communicating with each other using an X.25communications protocol. The X.25 communications protocol may comply orbe compatible with a standard promulgated by the InternationalTelecommunication Union-Telecommunication Standardization Sector(ITU-T). Alternatively or additionally, the communication devices may becapable of communicating with each other using a frame relaycommunications protocol. The frame relay communications protocol maycomply or be compatible with a standard promulgated by ConsultativeCommittee for International Telegraph and Telephone (CCITT) and/or theAmerican National Standards Institute (ANSI). Alternatively oradditionally, the transceivers may be capable of communicating with eachother using an Asynchronous Transfer Mode (ATM) communications protocol.The ATM communications protocol may comply or be compatible with an ATMstandard published by the ATM Forum titled “ATM-MPLS NetworkInterworking 2.0” published August 2001, and/or later versions of thisstandard. Of course, different and/or after-developedconnection-oriented network communication protocols are equallycontemplated herein.

Unless specifically stated otherwise as apparent from the foregoingdisclosure, it is appreciated that, throughout the foregoing disclosure,discussions using terms such as “processing,” “computing,”“calculating,” “determining,” “displaying,” or the like, refer to theaction and processes of a computer system, or similar electroniccomputing device, that manipulates and transforms data represented asphysical (electronic) quantities within the computer system's registersand memories into other data similarly represented as physicalquantities within the computer system memories or registers or othersuch information storage, transmission or display devices.

One or more components may be referred to herein as “configured to,”“configurable to,” “operable/operative to,” “adapted/adaptable,” “ableto,” “conformable/conformed to,” etc. Those skilled in the art willrecognize that “configured to” can generally encompass active-statecomponents and/or inactive-state components and/or standby-statecomponents, unless context requires otherwise.

The terms “proximal” and “distal” are used herein with reference to aclinician manipulating the handle portion of the surgical instrument.The term “proximal” refers to the portion closest to the clinician andthe term “distal” refers to the portion located away from the clinician.It will be further appreciated that, for convenience and clarity,spatial terms such as “vertical”, “horizontal”, “up”, and “down” may beused herein with respect to the drawings. However, surgical instrumentsare used in many orientations and positions, and these terms are notintended to be limiting and/or absolute.

Those skilled in the art will recognize that, in general, terms usedherein, and especially in the appended claims (e.g., bodies of theappended claims) are generally intended as “open” terms (e.g., the term“including” should be interpreted as “including but not limited to,” theterm “having” should be interpreted as “having at least,” the term“includes” should be interpreted as “includes but is not limited to,”etc.). It will be further understood by those within the art that if aspecific number of an introduced claim recitation is intended, such anintent will be explicitly recited in the claim, and in the absence ofsuch recitation no such intent is present. For example, as an aid tounderstanding, the following appended claims may contain usage of theintroductory phrases “at least one” and “one or more” to introduce claimrecitations. However, the use of such phrases should not be construed toimply that the introduction of a claim recitation by the indefinitearticles “a” or “an” limits any particular claim containing suchintroduced claim recitation to claims containing only one suchrecitation, even when the same claim includes the introductory phrases“one or more” or “at least one” and indefinite articles such as “a” or“an” (e.g., “a” and/or “an” should typically be interpreted to mean “atleast one” or “one or more”); the same holds true for the use ofdefinite articles used to introduce claim recitations.

In addition, even if a specific number of an introduced claim recitationis explicitly recited, those skilled in the art will recognize that suchrecitation should typically be interpreted to mean at least the recitednumber (e.g., the bare recitation of “two recitations,” without othermodifiers, typically means at least two recitations, or two or morerecitations). Furthermore, in those instances where a conventionanalogous to “at least one of A, B, and C, etc.” is used, in generalsuch a construction is intended in the sense one having skill in the artwould understand the convention (e.g., “a system having at least one ofA, B, and C” would include but not be limited to systems that have Aalone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together, etc.). In those instances where aconvention analogous to “at least one of A, B, or C, etc.” is used, ingeneral such a construction is intended in the sense one having skill inthe art would understand the convention (e.g., “a system having at leastone of A, B, or C” would include but not be limited to systems that haveA alone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together, etc.). It will be furtherunderstood by those within the art that typically a disjunctive wordand/or phrase presenting two or more alternative terms, whether in thedescription, claims, or drawings, should be understood to contemplatethe possibilities of including one of the terms, either of the terms, orboth terms unless context dictates otherwise. For example, the phrase “Aor B” will be typically understood to include the possibilities of “A”or “B” or “A and B.”

With respect to the appended claims, those skilled in the art willappreciate that recited operations therein may generally be performed inany order. Also, although various operational flow diagrams arepresented in a sequence(s), it should be understood that the variousoperations may be performed in other orders than those which areillustrated, or may be performed concurrently. Examples of suchalternate orderings may include overlapping, interleaved, interrupted,reordered, incremental, preparatory, supplemental, simultaneous,reverse, or other variant orderings, unless context dictates otherwise.Furthermore, terms like “responsive to,” “related to,” or otherpast-tense adjectives are generally not intended to exclude suchvariants, unless context dictates otherwise.

It is worthy to note that any reference to “one aspect,” “an aspect,”“an exemplification,” “one exemplification,” and the like means that aparticular feature, structure, or characteristic described in connectionwith the aspect is included in at least one aspect. Thus, appearances ofthe phrases “in one aspect,” “in an aspect,” “in an exemplification,”and “in one exemplification” in various places throughout thespecification are not necessarily all referring to the same aspect.Furthermore, the particular features, structures or characteristics maybe combined in any suitable manner in one or more aspects.

Any patent application, patent, non-patent publication, or otherdisclosure material referred to in this specification and/or listed inany Application Data Sheet is incorporated by reference herein, to theextent that the incorporated materials is not inconsistent herewith. Assuch, and to the extent necessary, the disclosure as explicitly setforth herein supersedes any conflicting material incorporated herein byreference. Any material, or portion thereof, that is said to beincorporated by reference herein, but which conflicts with existingdefinitions, statements, or other disclosure material set forth hereinwill only be incorporated to the extent that no conflict arises betweenthat incorporated material and the existing disclosure material.

In summary, numerous benefits have been described which result fromemploying the concepts described herein. The foregoing description ofthe one or more forms has been presented for purposes of illustrationand description. It is not intended to be exhaustive or limiting to theprecise form disclosed. Modifications or variations are possible inlight of the above teachings. The one or more forms were chosen anddescribed in order to illustrate principles and practical application tothereby enable one of ordinary skill in the art to utilize the variousforms and with various modifications as are suited to the particular usecontemplated. It is intended that the claims submitted herewith definethe overall scope.

1. A method for characterizing a state of an end effector of anultrasonic device, the ultrasonic deice comprising an electromechanicalultrasonic system defined by a predetermined resonant frequency, theelectromechanical ultrasonic system further comprising an ultrasonictransducer coupled to an ultrasonic blade, the method comprising:applying, by an energy source, a power level to the ultrasonictransducer; measuring, by a control circuit coupled to a memory, animpedance value of the ultrasonic transducer; comparing, by the controlcircuit, the impedance value to a reference impedance value stored inthe memory; classifying, by the control circuit, the impedance valuebased on the comparison; characterizing, by the control circuit, thestate of the electromechanical ultrasonic system based on theclassification of the impedance value; and adjusting, by the controlcircuit, the power level applied to the ultrasonic transducer based onthe characterization of the state of the end effector.
 2. The method ofclaim 1, wherein measuring, by a control circuit coupled to a memory, animpedance value of the ultrasonic transducer comprises measuring acomplex impedance value defined as a ratio of a voltage signal Vg(t)applied by the energy source to the ultrasonic transducer to a currentsignal Ig(t) applied by the energy source to the ultrasonic transducer.3. The method of claim 2, wherein comparing, by the control circuit, theimpedance value to a reference impedance value stored in the memorycomprises comparing, by the control circuit, the impedance value to adata point in a reference complex impedance characteristic pattern. 4.The method of claim 1, wherein measuring, by a control circuit coupledto a memory, an impedance value of the ultrasonic transducer comprises:applying, by the energy source, a drive signal to the ultrasonictransducer, wherein the drive signal is a periodic signal defined by amagnitude and a frequency; sweeping, by the control circuit, thefrequency of the drive signal from below a first resonance to above thefirst resonance of the electromechanical ultrasonic system; andmeasuring and recording, by the control circuit, impedance/admittancecircle variables Re, Ge, Xe, and Be.
 5. The method of claim 4, whereincomparing, by the control circuit, the impedance value to referenceimpedance value stored in the memory comprises comparing, by the controlcircuit, the measured impedance/admittance circle variables Re, Ge, Xe,Be to the reference impedance/admittance circle variables Rref, Gref,Xref, and Bref.
 6. The method of claim 1, wherein characterizing, by thecontrol circuit, the state of the electromechanical ultrasonic systembased on the classification of the impedance value comprises determiningthe proper installation of two or more components of the ultrasonicdevice.
 7. The method of claim 1, wherein characterizing, by the controlcircuit, the state of the electromechanical ultrasonic system based onthe classification of the impedance value comprises determining anamount of power delivered to the ultrasonic device by the energy sourceto compensate for an articulation angle of an articulatable ultrasonicblade coupled to the ultrasonic transducer.
 8. A method forcharacterizing a function of an end effector of an ultrasonic device,the ultrasonic deice comprising an electromechanical ultrasonic systemdefined by a predetermined resonant frequency, the electromechanicalultrasonic system further comprising an ultrasonic transducer coupled toan ultrasonic blade, the method comprising: applying, by an energysource, a power level to the ultrasonic transducer, measuring, by acontrol circuit coupled to a memory, an impedance value of theultrasonic transducer, comparing, by the control circuit, the impedancevalue to a reference impedance value stored in the memory; classifying,by the control circuit, the impedance value based on the comparison;characterizing, by the control circuit, the function of theelectromechanical ultrasonic system based on the classification of theimpedance value; and adjusting, by the control circuit, the power levelapplied to the ultrasonic transducer based on the characterization ofthe function of the end effector.
 9. The method of claim 8, whereinmeasuring, by a control circuit coupled to a memory, an impedance valueof the ultrasonic transducer comprises measuring a complex impedancevalue defined as a ratio of a voltage signal Vg(t) applied by the energysource to the ultrasonic transducer to a current signal Ig(t) applied bythe energy source to the ultrasonic transducer.
 10. The method of claim9, wherein comparing, by the control circuit, the impedance value to areference impedance value stored in the memory comprises comparing, bythe control circuit, the impedance value to a data point in a referencecomplex impedance characteristic pattern.
 11. The method of claim 8,wherein adjusting, by the control circuit, the power level applied tothe ultrasonic transducer based on the characterization of the functionof the end effector comprises adjusting, by the control circuit, thepower level applied to the ultrasonic transducer based on adetermination that a tissue transection process is complete.
 12. Themethod of claim 8, wherein characterizing, by the control circuit, thefunction of the electromechanical ultrasonic system based on theclassification of the impedance value comprises determining, by thecontrol circuit, that the ultrasonic blade is contacting a vessel. 13.The method of claim 12, wherein measuring, by a control circuit coupledto a memory, an impedance value of the ultrasonic transducer comprisesmeasuring, by the control circuit, a complex impedance of the ultrasonictransducer, wherein the complex impedance is defined as${Z_{g}(t)} = {\frac{V_{g}(t)}{I_{g}(t)}.}$
 14. The method of claim 13,further comprising: receiving, by the control circuit, a compleximpedance measurement data point; comparing, by the control circuit, thecomplex impedance measurement data point to a data point in a referencecomplex impedance characteristic pattern; classifying, by the controlcircuit, the complex impedance measurement data point based on a resultof the comparison analysis; and determining, by the control circuit,that the ultrasonic blade is contacting the vessel based on the resultof the comparison analysis.
 15. The method of claim 12, furthercomprising generating, by the control circuit, a warning that theultrasonic blade is contacting the vessel.
 16. A method forcharacterizing a tissue in contact with an end effector of an ultrasonicdevice, the ultrasonic deice comprising an electromechanical ultrasonicsystem defined by a predetermined resonant frequency, theelectromechanical ultrasonic system further comprising an ultrasonictransducer coupled to an ultrasonic blade, the method comprising:applying, by an energy source, a power level to the ultrasonictransducer, measuring, by a control circuit coupled to a memory, animpedance value of the ultrasonic transducer, comparing, by the controlcircuit, the impedance value to a reference impedance value stored inthe memory; classifying, by the control circuit, the impedance valuebased on the comparison; characterizing, by the control circuit, thetissue in contact with the end effector based on the classification ofthe impedance value; and adjusting, by the control circuit, the powerlevel applied to the ultrasonic transducer based on the characterizationof the tissue in contact with the end effector.
 17. The method of claim16, wherein measuring, by a control circuit coupled to a memory, animpedance value of the ultrasonic transducer comprises measuring acomplex impedance value defined as a ratio of a voltage signal Vg(t)applied by the energy source to the ultrasonic transducer to a currentsignal Ig(t) applied by the energy source to the ultrasonic transducer.18. The method of claim 17, further comprising: pulsing, by the controlcircuit, the power level delivered to the ultrasonic transducer by theenergy source; determining, by the control circuit, changes in tissuecharacteristics of tissue located in the end effector, wherein thechanges in tissue characteristics is determined between pulses; andadjusting, by the processor or control circuit, power delivered to theultrasonic transducer based on the tissue changes.
 19. The method ofclaim 16, wherein measuring, by a control circuit coupled to a memory,an impedance value of the ultrasonic transducer comprises: applying, bythe energy source, a drive signal to the ultrasonic transducer, whereinthe drive signal is a periodic signal defined by a magnitude and afrequency; sweeping, by the control circuit, the frequency of the drivesignal from below a first resonance to above the first resonance of theelectromechanical ultrasonic system; and measuring and recording, by thecontrol circuit, impedance/admittance circle variables Re, Ge, Xe, andBe.
 20. The method of claim 16, wherein characterizing, by the controlcircuit, the tissue in contact with the end effector based on theclassification of the impedance value comprises classifying the tissueinto a distinct group in live time.